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Popular high-order schemes with compact stencils for Computational Fluid Dynamics (CFD) include Discontinuous Galerkin (DG), Spectral Difference (SD), and Spectral Volume (SV) methods. The recently proposed Flux Reconstruction (FR) approach or Correction Procedure using Reconstruction (CPR) is based on a differential formulation and provides a unifying framework for these high-order schemes. Here we present a brief review of recent developments for the FR/CPR schemes as well as some pacing items.

A computational fluid dynamics study was conducted to evaluate the feasibility of the variable-pitch split-blade supersonic fan concept. This fan configuration was conceived as a means to enable a supersonic fan to switch from the supersonic through-flow type of operation at high speeds to a conventional fan with subsonic inflow and outflow at low speeds. During this off-design, low-speed mode of operation, the fan would operate with a substantial static pressure rise across the blade row like a conventional transonic fan; the front (variable-pitch) blade would be aligned with the incoming flow, and the aft blade would remain fixed in the position set by the supersonic design conditions. Because of these geometrical features, this low speed configuration would inherently have a large amount of turning and, thereby, would have the potential for a large total pressure increase in a single stage. Such a high-turning blade configuration is prone to flow separation; it was hoped that the channeling of the flow between the blades would act like a slotted wing and help alleviate this problem. A total of 20 blade configurations representing various supersonic and transonic configurations were evaluated using a Navier Stokes CFD program called ADAPTNS because of its adaptive grid features. The flow fields generated by this computational procedure were processed by another data reduction program which calculated average flow properties and simulated fan performance. These results were employed to make quantitative comparisons and evaluations of blade performance. The supersonic split-blade configurations generated performance comparable to a single-blade supersonic, through-flow fan configuration. Simulated rotor total pressure ratios of the order of 2.5 or better were achieved for Mach 2.0 inflow conditions. The corresponding fan efficiencies were approximately 75 percent or better. The transonic split-blade configurations having large amounts of turning were able to generate large amounts of total turning and achieve simulated total pressure ratios of 3.0 or better with subsonic inflow conditions. These configurations had large losses and low fan efficiencies in the 70's percent. They had large separated regions and low velocity wakes. Additional turning and diffusion of this flow in a subsequent stator row would probably be very inefficient. The high total pressure ratios indicated by the rotor performance would be substantially reduced by the stators, and the stage efficiency would be substantially lower. Such performance leaves this dual-mode fan concept less attractive than originally postulated.

The hierarchy of codes; boundary layers and turbulence models; uniqueness and artificial viscosity; efficiency of solution algorithms; data display and analysis; and cost of experimental validation are briefly examined.

Patched-grid algorithms for the analysis of complex configurations with an implicit, upwind-biased Navier-Stokes solver were investigated. Conservative and non-conservative approaches for performing zonal interpolations were implemented. The latter approach yields the most flexible technique in that it can handle both patched and overlaid grids. Results for a two-dimensional blunt body problem show that either approach yield accurate steady-state shock locations and jump conditions. In addition, calculations of the turbulent flow through a hypersonic inlet on a three-zone grid show that the numerical prediction is in good agreement with the experimental results. Through the use of a generalized coordinate transformation at the zonal interface between two or more blocks, the algorithm can be applied to highly stretched viscous grids and to arbitrarily-shaped zonal boundaries. Applications were made to the F-18 aircraft at subsonic, high-alpha conditions, in support of the NASA High-Alpha Research Program. The calculations were compared to ground-based and flight test experiments and were used as a guide to understanding the ground-based tests, which are laminar and transitional, and their relationship to flight. Calculations about a complete reconnaissance aircraft were also performed in order to further demonstrate the capability of the patched-grid algorithm.

A steady incompressible three-dimensional (3-D) viscous flow analysis was conducted for the Space Shuttle Main Propulsion External Tank (ET)/Orbiter (ORB) propellant feed line quick separable 17-inch disconnect flapper valves for liquid oxygen (LO2) and liquid hydrogen (LH2). The main objectives of the analysis were to predict and correlate the hydrodynamic stability of the flappers and pressure drop with available water test data. Computational Fluid Dynamics (CFD) computer codes were procured at no cost from the public domain, and were modified and extended to carry out the disconnect flow analysis. The grid generator codes SVTGD3D and INGRID were obtained. NASA Ames Research Center supplied the flow solution code INS3D, and the color graphics code PLOT3D. A driver routine was developed to automate the grid generation process. Components such as pipes, elbows, and flappers can be generated with simple commands, and flapper angles can be varied easily. The flow solver INS3D code was modified to treat interior flappers, and other interfacing routines were developed, which include a turbulence model, a force/moment routine, a time-step routine, and initial and boundary conditions. In particular, an under-relaxation scheme was implemented to enhance the solution stability. Major physical assumptions and simplifications made in the analysis include the neglect of linkages, slightly reduced flapper diameter, and smooth solid surfaces. A grid size of 54 x 21 x 25 was employed for both the LO2 and LH2 units. Mixing length theory applied to turbulent shear flow in pipes formed the basis for the simple turbulence model. Results of the analysis are presented for LO2 and LH2 disconnects.

Information on computational fluid dynamics (CFD) research and applications carried out at the NASA Langley Research Center is given in viewgraph form. The Langley CFD strategy, the five-year plan in CFD and flow physics, 3-block grid topology, the effect of a patching algorithm, F-18 surface flow, entropy and vorticity effects that improve accuracy of unsteady transonic small disturbance theory, and the effects of reduced frequency on first harmonic components of unsteady pressures due to airfoil pitching are among the topics covered.

The role of experiment in the development of Computational Fluid Dynamics (CFD) for aerodynamic flow field prediction is discussed. Requirements for code verification from two sources that pace the development of CFD are described for: (1) development of adequate flow modeling, and (2) establishment of confidence in the use of CFD to predict complex flows. The types of data needed and their accuracy differs in detail and scope and leads to definite wind tunnel requirements. Examples of testing to assess and develop turbulence models, and to verify code development, are used to establish future wind tunnel testing requirements. Versatility, appropriate scale and speed range, accessibility for nonintrusive instrumentation, computerized data systems, and dedicated use for verification were among the more important requirements identified.

This report describes a computational study to understand the free roll, pitch, and yaw motion of a canard-controlled, fin-stabilized projectile. Numerical computations were performed for this projectile using an advanced coupled computational fluid dynamics and rigid body dynamics technique. Additionally, the coupled approach was tailored to be constraints-based for the rigid body dynamics allowing for pure pitching and pure rolling motions to be studied prior to considering the full roll-pitch-yaw motion. Flow visualizations and aerodynamic force and moment computations indicate unsteady canard stall at high angle of attack and significant interaction of these canard vortices on the afterbody-fins. Parameter estimation was performed to obtain aerodynamic coefficients, assess the aerodynamic model, and understand the roll-pitch-yaw coupling. These results suggest that improvements to aerodynamic modeling are necessary to better capture high angle-of-attack phenomenon such as unsteady canard stall and vortex interactions. Analysis of the pure pitch and pure roll predicts the coupled roll-pitch-yaw motion well with the exception of unsteady and interaction effects during periods of high angle of attack.

The activation of spoilers on the upper surface of a wing is a relatively new method of achieving longitudinal and lateral control of ram-air canopies, often referred to as parafoils. No numerical studies, however, have fully investigated the 3-D aerodynamic performance of these bleed-air actuators. Simulation results are presented for a finite span, ram-air canopy geometry and several configurations amenable for comparison with wind tunnel experiments and flight test data. Assessments are also made between the resulting flowfields and previously reported 2-D computational fluid dynamics (CFD) results. Evaluations include cases with an asymmetrical trailing edge deflection to simulate a turn and the inclusion of two different bleed-air vents. Lift, drag and roll coefficients correlate well with wind tunnel and flight test results.

Anatomically accurate computational fluid dynamics (CFD) models of the nasal passages of an infant (6 months old, 1.3 kg) and adult (7 years old, 11.9 kg) rhesus monkey were used to predict deposition of inhaled nano- and micro-particles. Steady-state, inspiratory airflow simulations were conducted in each model at flow rates equal to 100%, 200%, and 300% of the estimated minute volume for resting breathing. Particle transport and deposition simulations were conducted using the Lagrangian method to track the motion of individual particles that were passively released from the nostrils. Semi-empirical curves for nasal deposition were developed based on the simulation data for nano- and micro-particle deposition to allow for simplified calculations of age-based nasal deposition in the rhesus monkey nasal passages that can be implemented into lung dosimetry models.

This report presents an overview of the software developed under the common high performance computing scalable software initiative (CHSSI), computational fluid dynamics (CFD) 6 project. Under the project, a proven zonal Navier-Stokes solver was rewritten for scalable parallel performance on both shared memory and distributed memory high performance computers. At the same time, a graphical user interface (GUl) was developed to help the user set up the problem, provide real-time visualization, and execute the solver. The GUl is not just an input interface but provides an environment for the systematic, coherent execution of the solver, thus making it a more useful, quicker and easier application tool for engineers. Also part of the CHSSI project is a demonstration of the developed software on complex applications of interest to the Department of Defense. Results from computations of 10 brilliant anti-armor (BAT) submunitions simultaneously ejecting from a single Army tactical missile and a guided multiple launch rocket system missile are discussed. Experimental data were available for comparison with the BAT computations. The CFD computations and the experimental data show good agreement and serve as validation for the accuracy of the solver.

A brief non-mathematical introduction to the subject of Computational Fluid Dynamics, (CFD), is given. Various approximations to the full flow equations are described and their suitability for modelling the aerodynamics of missiles is discussed. A number of CFD codes available in the UK which are applicable to missile aerodynamics are considered. Each code is described briefly and comparisons between prediction and measurement are shown. Keywords: Great Britain, Navier stokes equations, Grids, Missile, Configurations.

Validation Of Computational Flight Dynamics was the subject of the 62 nd Meeting of the Fluid Dynamics Panel. The Call-for-Papers was focused on a compilation of the State of Art of Validation of computer codes, to insure, that the mathematical and numerical schemes employed in the code model correctly the critical physics of the flow field. This ambitious aim was reached only to a degree by comparison of experimental and computational data. But at least some of the papers have attempted to validate computer codes by the use of recently developed Data Bases providing also detailed information on 3D-flow field characteristics. The reviewer summarizes the papers, comments on the overall program, and tries to identify existent gaps for future work. The ultimate goal of CFD development is a fully mature design and analysis capability, that is user friendly, cost effective, numerical accurate and fully verified by detailed experimental comparisons. CFD code validation is accomplished by detailed flow field comparison numerical solutions with experimental data to insure that the mathematical and numerical schemes employed in the code accurately model the critical physics of the flow field. The symposium will concentrate on the validation of computational methods. The objectives are to identify the level of agreement of physical models and numerical solution algorithms with experimental data; to identify regions of validity for given flow solvers; and to identify flow regimes where significant gaps exist and further work is warranted.

Symposia contents: Validation of a Multi-Block Euler Flow Solver with Propeller-SlipStream Flows; Investigation of the Surface Flow on Conical Bodies at High Subsonic and Supersonic Speeds; Design and Validation of a 2D Euler Code; Finite Difference Methods in Recirculating Flows; The Design of the Garteur Low Aspect-Ratio Wing for use in the Validation of Shear Layer and Overall Flow Prediction Methods; Slender Cone CFD and Experimental Data Comparisons in Hypersonic Flow; Validation of a User-Friendly CFD Code for Prediction of the Aerodynamic Characteristics of Flight Vehicles; Comparison of Theory and Experiment for Four Supercritical, Low Drag Airfoils; Solution Error Estimation in the Numerical Predictions of Turbulent Recirculating Flows; Detailed Flowfield Measurements Over a 75-Degree Swept Delta Wing for Code Validation; Experiments and Code Validation for Juncture Flows; Accuracy and Efficiency of a Time Marching Approach for Combustor Modeling; Large-Scale Viscous Simulation of Laminar Vortex Flow over a Delta Wing; and Investigation of the Accuracy of Finite Volume Methods For 2-and 3-Dimensional Flows.

-computational fluid dynamics; a computational fluid dynamics model of flow and settling in sedimentation tanks; advances in computational fluid dynamics applied to the greenhouse environment; fluid dynamics analysis of a space vehicle entering the mars atmosphere; air movement within enclosed road-objects with contra-traffica cdf-investigation; computational fluid dynamics and discrete element method applied to centrifuges; cfd and thermography techniques applied in cooling systems designs; computational fluid dynamics modelling of photochemical reactors; aerodynamic design of the vertical takeoff hopper concept of future launchers preparatory program; fluid-structure interaction of a radial turbine; industrial sprays-experimental characterization and numerical modeling; multidimensional design of hydraulic components and systems; study of an individual air-conditioning energy-saving equipment; unsteady differentiation of aerodynamic coefficients-methodology and applications; use of fluid dynamic simulation to improve the design of spouted beds-

-computational fluid dynamics; a computational fluid dynamics model of flow and settling in sedimentation tanks; advances in computational fluid dynamics applied to the greenhouse environment; fluid dynamics analysis of a space vehicle entering the mars atmosphere; air movement within enclosed road-objects with contra-traffica cdf-investigation; computational fluid dynamics and discrete element method applied to centrifuges; cfd and thermography techniques applied in cooling systems designs; computational fluid dynamics modelling of photochemical reactors; aerodynamic design of the vertical takeoff hopper concept of future launchers preparatory program; fluid-structure interaction of a radial turbine; industrial sprays-experimental characterization and numerical modeling; multidimensional design of hydraulic components and systems; study of an individual air-conditioning energy-saving equipment; unsteady differentiation of aerodynamic coefficients-methodology and applications; use of fluid dynamic simulation to improve the design of spouted beds-

-computational fluid dynamics; a computational fluid dynamics model of flow and settling in sedimentation tanks; advances in computational fluid dynamics applied to the greenhouse environment; fluid dynamics analysis of a space vehicle entering the mars atmosphere; air movement within enclosed road-objects with contra-traffica cdf-investigation; computational fluid dynamics and discrete element method applied to centrifuges; cfd and thermography techniques applied in cooling systems designs; computational fluid dynamics modelling of photochemical reactors; aerodynamic design of the vertical takeoff hopper concept of future launchers preparatory program; fluid-structure interaction of a radial turbine; industrial sprays-experimental characterization and numerical modeling; multidimensional design of hydraulic components and systems; study of an individual air-conditioning energy-saving equipment; unsteady differentiation of aerodynamic coefficients-methodology and applications; use of fluid dynamic simulation to improve the design of spouted beds-

-computational fluid dynamics; a computational fluid dynamics model of flow and settling in sedimentation tanks; advances in computational fluid dynamics applied to the greenhouse environment; fluid dynamics analysis of a space vehicle entering the mars atmosphere; air movement within enclosed road-objects with contra-traffica cdf-investigation; computational fluid dynamics and discrete element method applied to centrifuges; cfd and thermography techniques applied in cooling systems designs; computational fluid dynamics modelling of photochemical reactors; aerodynamic design of the vertical takeoff hopper concept of future launchers preparatory program; fluid-structure interaction of a radial turbine; industrial sprays-experimental characterization and numerical modeling; multidimensional design of hydraulic components and systems; study of an individual air-conditioning energy-saving equipment; unsteady differentiation of aerodynamic coefficients-methodology and applications; use of fluid dynamic simulation to improve the design of spouted beds-

A method for inverse design of horizontal axis wind turbines (HAWTs) is presented in this paper. The direct solver for aerodynamic analysis solves the Reynolds Averaged Navier Stokes (RANS) equations, where the effect of the turbine rotor is modeled as momentum sources using the actuator disk model (ADM); this approach is referred to as RANS/ADM. The inverse problem is posed as follows: for a given selection of airfoils, the objective is to find the blade geometry (described as blade twist and chord distributions) which realizes the desired turbine aerodynamic performance at the design point; the desired performance is prescribed as angle of attack ($\alpha$) and axial induction factor ($a$) distributions along the blade. An iterative approach is used. An initial estimate of blade geometry is used with the direct solver (RANS/ADM) to obtain $\alpha$ and $a$. The differences between the calculated and desired values of $\alpha$ and $a$ are computed and a new estimate for the blade geometry (chord and twist) is obtained via nonlinear least squares regression using the Trust-Region-Reflective (TRF) method. This procedure is continued until the difference between the calculated and the desired values is within acceptable tolerance. The method is demonstrated for conventional, single-rotor HAWTs and then extended to multi-rotor, specifically dual-rotor wind turbines. The TRF method is also compared with the multi-dimensional Newton iteration method and found to provide better convergence when constraints are imposed in blade design, although faster convergence is obtained with the Newton method for unconstrained optimization.

We introduce a modified and simplified version of the pre-existing fully parallelized three-dimensional Navier--Stokes flow solver known as TPLS. We demonstrate how the simplified version can be used as a pedagogical tool for the study of computational fluid dynamics and parallel computing. TPLS is at its heart a two-phase flow solver, and uses calls to a range of external libraries to accelerate its performance. However, in the present context we narrow the focus of the study to basic hydrodynamics and parallel computing techniques, and the code is therefore simplified and modified to simulate pressure-driven single-phase flow in a channel, using only relatively simple Fortran 90 code with MPI parallelization, but no calls to any other external libraries. The modified code is analysed in order to both validate its accuracy and investigate its scalability up to 1000 CPU cores. Simulations are performed for several benchmark cases in pressure-driven channel flow, including a turbulent simulation, wherein the turbulence is incorporated via the large-eddy simulation technique. The work may be of use to advanced undergraduate and graduate students as an introductory study in computational fluid dynamics, while also providing insight for those interested in more general aspects of high-performance computing.

The needs for Computational Fluid Dynamics (CFD) in connection with student and faculty activities in the engineering departments at NPS are reviewed. Emphasis is placed on internal, propulsion related flows. Currently available CFD codes are also reviewe

Validation is the assessment of the accuracy of computational simulations by comparison with experimental data. A well validated computational fluid dynamics model can be of high importance when assessing the safety of medical devices. However, its validation and verification must be conducted before the results can be considered credible. The U.S. Food and Drug Administration has completed a computational inter-laboratory study that showed relatively negative current state of numerical methods used for simulating fluid flow in an idealized medical device, even by self-ascribed experts. Yet, the same numerical methods are commonly used to simulate fluid flow in much more complex geometries, especially when patient-specific geometries need to be used. The study presented here recreated these results with larger number of participants and confirmed the need for proper validation of the numerical methods used. Moreover, the results were analyzed with respect to the use of grid refinement study by the participants.

At the present time the efforts on this project are organized into two areas: the development of an approximate stagnation point solution and approximate flowfield studies which can be used to develop and investigate shock jump, electron temperature, radiation, vibration-dissociation coupling, and chemistry models. Progress in each area is discussed.

Some recent developments in acceleration of convergence methods for vector sequences are reviewed. The methods considered are the minimal polynomial extrapolation, the reduced rank extrapolation, and the modified minimal polynomial extrapolation. The vector sequences to be accelerated are those that are obtained from the iterative solution of linear or nonlinear systems of equations. The convergence and stability properties of these methods as well as different ways of numerical implementation are discussed in detail. Based on the convergence and stability results, strategies that are useful in practical applications are suggested. Two applications to computational fluid mechanics involving the three dimensional Euler equations for ducted and external flows are considered. The numerical results demonstrate the usefulness of the methods in accelerating the convergence of the time marching techniques in the solution of steady state problems.

Some recent developments in acceleration of convergence methods for vector sequences are reviewed. The methods considered are the minimal polynomial extrapolation, the reduced rank extrapolation, and the modified minimal polynomial extrapolation. The vector sequences to be accelerated are those that are obtained from the iterative solution of linear or nonlinear systems of equations. The convergence and stability properties of these methods as well as different ways of numerical implementation are discussed in detail. Based on the convergence and stability results, strategies that are useful in practical applications are suggested. Two applications to computational fluid mechanics involving the three dimensional Euler equations for ducted and external flows are considered. The numerical results demonstrate the usefulness of the methods in accelerating the convergence of the time marching techniques in the solution of steady state problems.

Some recent developments in acceleration of convergence methods for vector sequences are reviewed. The methods considered are the minimal polynomial extrapolation, the reduced rank extrapolation, and the modified minimal polynomial extrapolation. The vector sequences to be accelerated are those that are obtained from the iterative solution of linear or nonlinear systems of equations. The convergence and stability properties of these methods as well as different ways of numerical implementation are discussed in detail. Based on the convergence and stability results, strategies that are useful in practical applications are suggested. Two applications to computational fluid mechanics involving the three dimensional Euler equations for ducted and external flows are considered. The numerical results demonstrate the usefulness of the methods in accelerating the convergence of the time marching techniques in the solution of steady state problems.

This work investigates the influence of wall treatment on the prediction accuracy of the k-ε and k-ω models, as well as the solid volume fraction, in a solid-liquid fluidized bed. The objective of the study is to explore the effects of different y+ values on the performance of these turbulence models and the prediction of solid-liquid fluidized bed behavior. Using the Eulerian-Eulerian approach, a multiphase flow model was employed to simulate the behavior of solid particles and liquid in a fluidized bed. The standard conservation equations of continuity and momentum were solved to describe the flow dynamics. The research findings indicate that the k-ε model exhibits higher sensitivity to near-wall mesh refinement when predicting y+ values compared to the k-ω model. The k-ω model, however, demonstrates reasonably accurate predictions within the y+ range of 30 to 45. Furthermore, the k-ε model outperforms the k-ω model in predicting solid volume fractions when the near-wall region is refined. These results highlight the significance of wall treatment and near-wall mesh refinement in accurately predicting turbulent flow behavior in liquid-solid fluidized beds. The study contributes to a better understanding of the performance of turbulence models and their applicability to solid liquid fluidized beds.

This work investigates the influence of wall treatment on the prediction accuracy of the k-ε and k-ω models, as well as the solid volume fraction, in a solid-liquid fluidized bed. The objective of the study is to explore the effects of different y+ values on the performance of these turbulence models and the prediction of solid-liquid fluidized bed behavior. Using the Eulerian-Eulerian approach, a multiphase flow model was employed to simulate the behavior of solid particles and liquid in a fluidized bed. The standard conservation equations of continuity and momentum were solved to describe the flow dynamics. The research findings indicate that the k-ε model exhibits higher sensitivity to near-wall mesh refinement when predicting y+ values compared to the k-ω model. The k-ω model, however, demonstrates reasonably accurate predictions within the y+ range of 30 to 45. Furthermore, the k-ε model outperforms the k-ω model in predicting solid volume fractions when the near-wall region is refined. These results highlight the significance of wall treatment and near-wall mesh refinement in accurately predicting turbulent flow behavior in liquid-solid fluidized beds. The study contributes to a better understanding of the performance of turbulence models and their applicability to solid liquid fluidized beds.

This work investigates the influence of wall treatment on the prediction accuracy of the k-ε and k-ω models, as well as the solid volume fraction, in a solid-liquid fluidized bed. The objective of the study is to explore the effects of different y+ values on the performance of these turbulence models and the prediction of solid-liquid fluidized bed behavior. Using the Eulerian-Eulerian approach, a multiphase flow model was employed to simulate the behavior of solid particles and liquid in a fluidized bed. The standard conservation equations of continuity and momentum were solved to describe the flow dynamics. The research findings indicate that the k-ε model exhibits higher sensitivity to near-wall mesh refinement when predicting y+ values compared to the k-ω model. The k-ω model, however, demonstrates reasonably accurate predictions within the y+ range of 30 to 45. Furthermore, the k-ε model outperforms the k-ω model in predicting solid volume fractions when the near-wall region is refined. These results highlight the significance of wall treatment and near-wall mesh refinement in accurately predicting turbulent flow behavior in liquid-solid fluidized beds. The study contributes to a better understanding of the performance of turbulence models and their applicability to solid liquid fluidized beds.

This work investigates the influence of wall treatment on the prediction accuracy of the k-ε and k-ω models, as well as the solid volume fraction, in a solid-liquid fluidized bed. The objective of the study is to explore the effects of different y+ values on the performance of these turbulence models and the prediction of solid-liquid fluidized bed behavior. Using the Eulerian-Eulerian approach, a multiphase flow model was employed to simulate the behavior of solid particles and liquid in a fluidized bed. The standard conservation equations of continuity and momentum were solved to describe the flow dynamics. The research findings indicate that the k-ε model exhibits higher sensitivity to near-wall mesh refinement when predicting y+ values compared to the k-ω model. The k-ω model, however, demonstrates reasonably accurate predictions within the y+ range of 30 to 45. Furthermore, the k-ε model outperforms the k-ω model in predicting solid volume fractions when the near-wall region is refined. These results highlight the significance of wall treatment and near-wall mesh refinement in accurately predicting turbulent flow behavior in liquid-solid fluidized beds. The study contributes to a better understanding of the performance of turbulence models and their applicability to solid liquid fluidized beds.

Experiments were conducted at NASA Ames Research Center to define multi-tasking software requirements for multiple-instruction, multiple-data stream (MIMD) computer architectures. The focus was on specifying solutions for algorithms in the field of computational fluid dynamics (CFD). The program objectives were to allow researchers to produce usable parallel application software as soon as possible after acquiring MIMD computer equipment, to provide researchers with an easy-to-learn and easy-to-use parallel software language which could be implemented on several different MIMD machines, and to enable researchers to list preferred design specifications for future MIMD computer architectures. Analysis of CFD algorithms indicated that extensions of an existing programming language, adaptable to new computer architectures, provided the best solution to meeting program objectives. The CoFORTRAN Language was written in response to these objectives and to provide researchers a means to experiment with parallel software solutions to CFD algorithms on machines with parallel architectures.

This article is from PLoS ONE , volume 8 . Abstract Background: The pathogenesis of empty nose syndrome (ENS) has not been elucidated so far. Though postulated, there remains a lack of experimental evidence about the roles of nasal aerodynamics on the development of ENS. Objective: To investigate the nasal aerodynamic features of ENS andto explore the role of aerodynamic changes on the pathogenesis of ENS. Methods: Seven sinonasal models were numerically constructed, based on the high resolution computed tomography images of seven healthy male adults. Bilateral radical inferior/middle turbinectomy were numerically performed to mimic the typical nasal structures of ENS-inferior turbinate (ENS-IT) and ENS-middle turbinate (ENS-MT). A steady laminar model was applied in calculation. Velocity, pressure, streamlines, air flux and wall shear stress were numerically investigated. Each parameter of normal structures was compared with those of the corresponding pathological models of ENS-IT and ENS-MT, respectively. Results: ENS-MT: Streamlines, air flux distribution, and wall shear stress distribution were generally similar to those of the normal structures; nasal resistances decreased. Velocities decreased locally, while increased around the sphenopalatine ganglion by 0.20±0.17m/s and 0.22±0.10m/s during inspiration and expiration, respectively. ENS-IT: Streamlines were less organized with new vortexes shown near the bottom wall. The airflow rates passing through the nasal olfactory area decreased by 26.27%±8.68% and 13.18%±7.59% during inspiration and expiration, respectively. Wall shear stresses, nasal resistances and local velocities all decreased. Conclusion: Our CFD simulation study suggests that the changes in nasal aerodynamics may play an essential role in the pathogenesis of ENS. An increased velocity around the sphenopalatine ganglion in the ENS-MT models could be responsible for headache in patients with ENS-MT. However, these results need to be validated in further studies with a larger sample size and more complicated calculating models.

The Fluid Dynamics Branch at the NASA Marshall Space Flight Center is preparing to support flight programs through analysis of a variety of cryogenic fluid management (CFM) applications. Many vehicles being considered for future manned missions to the moon and beyond use chemical or nuclear thermal propulsion systems that rely on cryogenic propellants. Storing cryogenic propellants for later use is a challenge, though. Many areas of active CFM research, testing, and design involve propellant conditioning to ensure propellant remains a usable liquid for propulsion. Multiple technologies may be used to achieve adequate conditioning including the subject of this paper, a jet-based mixer. Mixing serves to homogenize fluid temperatures and decrease ullage pressure. Development and validation of a modeling methodology for jet-based mixing was conducted to prepare for in-line design work.

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate OpenMP-based parallel programs with nominal user assistance. We outline techniques used in the implementation of the tool and discuss the application of this tool on the NAS Parallel Benchmarks and several computational fluid dynamics codes. This work demonstrates the great potential of using the tool to quickly port parallel programs and also achieve good performance that exceeds some of the commercial tools.

Automatic differentiation (AD) is a powerful computational method that provides for computing exact sensitivity derivatives (SD) from existing computer programs for multidisciplinary design optimization (MDO) or in sensitivity analysis. A pre-compiler AD tool for FORTRAN programs called ADIFOR has been developed. The ADIFOR tool has been easily and quickly applied by NASA Langley researchers to assess the feasibility and computational impact of AD in MDO with several different FORTRAN programs. These include a state-of-the-art three dimensional multigrid Navier-Stokes flow solver for wings or aircraft configurations in transonic turbulent flow. With ADIFOR the user specifies sets of independent and dependent variables with an existing computer code. ADIFOR then traces the dependency path throughout the code, applies the chain rule to formulate derivative expressions, and generates new code to compute the required SD matrix. The resulting codes have been verified to compute exact non-geometric and geometric SD for a variety of cases. in less time than is required to compute the SD matrix using centered divided differences.

Distributed-memory parallel computers dominate today's parallel computing arena. These machines, such as Intel Paragon, IBM SP2, and Cray Origin2OO, have successfully delivered high performance computing power for solving some of the so-called "grand-challenge" problems. Despite initial success, parallel machines have not been widely accepted in production engineering environments due to the complexity of parallel programming. On a parallel computing system, a task has to be partitioned and distributed appropriately among processors to reduce communication cost and to attain load balance. More importantly, even with careful partitioning and mapping, the performance of an algorithm may still be unsatisfactory, since conventional sequential algorithms may be serial in nature and may not be implemented efficiently on parallel machines. In many cases, new algorithms have to be introduced to increase parallel performance. In order to achieve optimal performance, in addition to partitioning and mapping, a careful performance study should be conducted for a given application to find a good algorithm-machine combination. This process, however, is usually painful and elusive. The goal of this project is to design and develop efficient parallel algorithms for highly accurate Computational Fluid Dynamics (CFD) simulations and other engineering applications. The work plan is 1) developing highly accurate parallel numerical algorithms, 2) conduct preliminary testing to verify the effectiveness and potential of these algorithms, 3) incorporate newly developed algorithms into actual simulation packages. The work plan has well achieved. Two highly accurate, efficient Poisson solvers have been developed and tested based on two different approaches: (1) Adopting a mathematical geometry which has a better capacity to describe the fluid, (2) Using compact scheme to gain high order accuracy in numerical discretization. The previously developed Parallel Diagonal Dominant (PDD) algorithm and Reduced Parallel Diagonal Dominant (RPDD) algorithm have been carefully studied on different parallel platforms for different applications, and a NASA simulation code developed by Man M. Rai and his colleagues has been parallelized and implemented based on data dependency analysis. These achievements are addressed in detail in the paper.

This study involves the development of numerical modelling in spray combustion. These modelling efforts are mainly motivated to improve the computational efficiency in the stochastic particle tracking method as well as to incorporate the physical submodels of turbulence, combustion, vaporization, and dense spray effects. The present mathematical formulation and numerical methodologies can be casted in any time-marching pressure correction methodologies (PCM) such as FDNS code and MAST code. A sequence of validation cases involving steady burning sprays and transient evaporating sprays will be included.

Several current challenges in computational fluid dynamics and aerothermodynamics for hypersonic vehicle applications are discussed. Example simulations are presented from code validation and code benchmarking efforts to illustrate capabilities and limitations. Opportunities to advance the state-of-art in algorithms, grid generation and adaptation, and code validation are identified. Highlights of diverse efforts to address these challenges are then discussed. One such effort to re-engineer and synthesize the existing analysis capability in LAURA, VULCAN, and FUN3D will provide context for these discussions. The critical (and evolving) role of agile software engineering practice in the capability enhancement process is also noted.

An overview of research activities at the United Technologies Research Center (UTRC) in the area of Computational Fluid Dynamics (CFD) is presented. The requirement and use of various levels of computers, including supercomputers, for the CFD activities is described. Examples of CFD directed toward applications to helicopters, turbomachinery, heat exchangers, and the National Aerospace Plane are included. Helicopter rotor codes for the prediction of rotor and fuselage flow fields and airloads were developed with emphasis on rotor wake modeling. Airflow and airload predictions and comparisons with experimental data are presented. Examples are presented of recent parabolized Navier-Stokes and full Navier-Stokes solutions for hypersonic shock-wave/boundary layer interaction, and hydrogen/air supersonic combustion. In addition, other examples of CFD efforts in turbomachinery Navier-Stokes methodology and separated flow modeling are presented. A brief discussion of the 3-tier scientific computing environment is also presented, in which the researcher has access to workstations, mid-size computers, and supercomputers.

Using Computational Fluid Dynamics (CFD) to predict a flow field is an approximation to the exact problem and uncertainties exist. There is a method to approximate the errors in CFD via Richardson's Extrapolation. This method is based off of progressive grid refinement. To estimate the errors in an unstructured grid, the analyst must interpolate between at least three grids. This paper describes a study to find an appropriate interpolation scheme that can be used in Richardson's extrapolation or other uncertainty method to approximate errors. Nomenclature

The Marshall Space Flight Center (MSFC) is the Center of Excellence for Space Propulsion Technology within NASA. One of MSFC's goals is to lower the cost of access to space. MSFC's Fluid Dynamics Division, a part of the Structures and Dynamics Lab, assists in accomplishing this goal. This division is divided into two branches: experimental and analytical, whose work is complimentary and integrated. In the analysis branch, the emphasis is to apply, rather than develop computational fluid dynamics (CFD), to reduce the cost of design and development of: (1) pump and turbine feedlines and feed manifolds; (2) all primary and secondary flow paths in pumps; (3) all primary and secondary flow paths in turbines; (4) combustion chambers; (5) rocket engine nozzles and plumes; and (6) launch vehicles ascent. The broad range of applications imposes unique constraints on the software. The use of CFD in evaluating rocket engine hardware, specifically, is of value due to several reasons: (1) Rocket engine hardware is extremely expensive to build and test; (2) high engineering and development cost is due to limited production; (3) the cost of one engine test is greater than the average yearly hardware and software cost; (4) CFD represents a relatively small investment relative to the impact it has on the engine development; and (5) computing costs are continuously decreasing. In terms of accuracy the predictable error is more useful than the inconsistent accuracy. The achievable accuracy varies from application to application. The lack of accuracy is often caused by improper analyses: such as improperly applied or located boundary conditions, or attempting steady analysis of unsteady flows. This report is in viewgraph format.

A thorough understanding of dynamic interactions between inlets and compressors is extremely important to the design and development of propulsion control systems, particularly for supersonic aircraft such as the High-Speed Civil Transport (HSCT). Computational fluid dynamics (CFD) codes are routinely used to analyze individual propulsion components. By coupling the appropriate CFD component codes, it is possible to investigate inlet-compressor interactions. The objectives of this work were to gain a better understanding of inlet-compressor interaction physics, formulate a more realistic compressor-face boundary condition for time-accurate CFD simulations of inlets, and to take a first step toward the CFD simulation of an entire engine by coupling multidimensional component codes. This work was conducted at the NASA Lewis Research Center by a team of civil servants and support service contractors as part of the High Performance Computing and Communications Program (HPCCP).

Computational fluid dynamics (CFD) is maturing, and is at a stage in its technological life cycle in which it is now routinely applied to some rather complicated problems; it is starting to create an impact on the design cycle of aerospace flight vehicles and their components. CFD is also being used to better understand the fluid physics of flows heretofore not understood, such as three-dimensional separation. CFD is also being used to complement and is being complemented by experiments. In this paper, the primary and secondary pacing items that govern CFD in the past are reviewed and updated. The future prospects of CFD are explored which will offer people working in the discipline challenges that should extend the technological life cycle to further increase the capabilities of a proven demonstrated technology.

Lewis is a multidisciplinary Center with strong research and development programs in aeronautical and space propulsion, power, space communications, space experiments and materials. Computational fluid dynamics (CFD) is playing an important and growing role in most of these areas. Described here is how CFD is integrated into these programs and highlights elements of the CFD activities. Examples are presented of codes developed to predict flow fields in advanced propulsion systems and several of the code validation experiments are described. The CFD effort at Lewis ranges from basic research on new and improved algorithms through code development to the application of these codes to specific engineering problems. Because of the substantial improvement in CFD's predictive capability, its use at Lewis is on a steep growth path, spreading rapidly into new areas which had not traditionally taken advantage of the techniques of numerical simulation. Multidisciplinary codes and the future direction of CFD at Lewis are discussed.

The ability to enhance detonation wave transmission at a diffraction plane through various shock reflection/focusing conditions was evaluated numerically. The geometry dimensions were generally representative of the condition existing in a valve-less pulse detonation engine developed by the Naval Postgraduate School and consisted of a small cylindrical \"initiator\" combustor, which transmitted a shock wave to a larger diameter combustor. The wall cross section of the larger combustor was varied to evaluate the increase in reflected shock temperature and pressure conditions, ultimately revealing the dramatic increase in local temperature for a \"scalloped\" outer wall condition over the cylindrical cross section cases. The initiator diameter was held constant and the larger combustor diameters varied in order to evaluate the effects of diameter ratio on the shock reflection conditions for both cylindrical and scalloped geometries. A computational fluid dynamics (CFD) solver known as OVERFLOW was used to model the fluid dynamic processes but was limited in capability to shock wave Mach numbers less than about 4.2.

The ability to enhance detonation wave transmission at a diffraction plane through various shock reflection/focusing conditions was evaluated numerically. The geometry dimensions were generally representative of the condition existing in a valve-less pulse detonation engine developed by the Naval Postgraduate School and consisted of a small cylindrical \"initiator\" combustor, which transmitted a shock wave to a larger diameter combustor. The wall cross section of the larger combustor was varied to evaluate the increase in reflected shock temperature and pressure conditions, ultimately revealing the dramatic increase in local temperature for a \"scalloped\" outer wall condition over the cylindrical cross section cases. The initiator diameter was held constant and the larger combustor diameters varied in order to evaluate the effects of diameter ratio on the shock reflection conditions for both cylindrical and scalloped geometries. A computational fluid dynamics (CFD) solver known as OVERFLOW was used to model the fluid dynamic processes but was limited in capability to shock wave Mach numbers less than about 4.2.

In the Membrane Bio-Reactor waste-water treatment system,The water production of membrane modules is an important parameter to measure the working efficiency of MBR system, while the internal pressure series MBR is a common membrane module connection method. Therefore, the calculation and analysis of the water production of internal pressure series MBR system by computational fluid dynamics is carried out. In the analysis process, the geometric model of the internal pressure series MBR system is first established by the CFD preprocessor and the mesh is divided. Then the CFD solver is used to calculate the water production of the model. Finally, the CFD post processor is used to present the calculation results in an image. On this basis, this paper has carried out a large number of experimental analysis. In the analysis process, this paper compares the calculation results of the solver with the actual operating system results of MBR. The comparison results show that the calculation results of the solver are basically consistent with the actual water production of membrane modules, and have higher calculation accuracy. It achieves the purpose of accurately calculating the water production of membrane modules, and solves the problem of measuring the working efficiency of MBR system by calculating the water production of membrane modules. which has certain reference value for MBR engineering design and research.

NAS 1.55:10038-Vol-2 Digitized from IA1177307-08-0020 , IA1177307-08-0021 , IA1177307-08-0022 , IA1177307-08-0023 , IA1177307-08-0024 , IA1177307-08-0025 .

tecnologie segrete

— The parameters affecting particle injection in a high pressure powder fuel injection system were verified by using computational particle fluid dynamics (CPFD). The particles were coal (í µí± í µí± =175 μm, ρ s = 1350 kg/m 3), and the simulation was performed by changing the clearance between the roller and the hose and by changing the total pressure drop. Also, the wall erosion of the hose was confirmed by changing the clearance. As the clearance decreases from 10 mm to 1 mm when the total pressure difference is 10 bar, it is confirmed that the injection of the particles is increased twofold , but the power of the motor should be increased to 1.45 times. When the clearance is 5mm, as the total pressure drop is increased from 10 bar to 30 bar, the particle injection rate decreases 0.33-fold, but the motor power must be increased 3-fold. Also, it was confirmed that the wall erosion of the hose was large when the clearance was 7 mm or more.

Alexander the Great was one of the most successful military commanders in history, and was undefeated in battle. By the time of his death, he had conquered most of the world known to the ancient Greeks.<br></br>Alexander the Great is one of many biographies aimed at young people written by Jacob Abbott and his brother. The biographies are written in such a way that makes them appealing and easily accessible to everyone. - Written by Wikipedia and Lizzie Driver

2Peter the Great

By Jacob Abbott

There are very few persons who have not heard of the fame of Peter the Great, the founder, as he is generally regarded by mankind, of Russian civilization. The celebrity, however, of the great Muscovite sovereign among young persons is due in a great measure to the circumstance of his having repaired personally to Holland, in the course of his efforts to introduce the industrial arts among his people, in order to study himself the art and mystery of shipbuilding, and of his having worked with his own hands in a ship-yard there. The little shop where Peter pursued these practical studies still stands in Saardam, a ship-building town not far from Amsterdam. The building is of wood, and is now much decayed; but, to preserve it from farther injury, it has been encased in a somewhat larger building of brick, and it is visited annually by great numbers of curious travelers.<br></br>The whole history of Peter, as might be expected from the indications of character developed by this incident, forms a narrative that is full of interest and instruction for all. (from the Preface of <i>Peter the Great</i>)

3Little Eve Edgarton

By Eleanor Hallowell Abbott

Eve Edgarton is not who she seems she is. A short encounter with Mr. Barton show that first impressions are not always right or indicative of one's seemingly obvious preference or one's proclivity. (Summary by Kehinde)

4Peace On Earth, Good-Will to Dogs

By Eleanor Hallowell Abbott

If you don't like Christmas stories, don't read this one!<br></br> And if you don't like dogs, I don't know just what to advise you to do!<br></br> For I warn you perfectly frankly that I am distinctly pro-dog and distinctly pro-Christmas, and would like to bring to this little story whatever whiff of fir-balsam I can cajole from the make-believe forest in my typewriter, and every glitter of tinsel, smudge of toy candle, crackle of wrapping paper, that my particular brand of brain and ink can conjure up on a single keyboard! And very large-sized dogs shall romp through every page! And the mercury shiver perpetually in the vicinity of zero! And every foot of earth be crusty-brown and bare with no white snow at all till the very last moment when you'd just about given up hope! And all the heart of the story is very,—oh very young!<br></br> For purposes of propriety and general historical authenticity there are of course parents in the story. And one or two other oldish persons. But they all go away just as early in the narrative as I can manage it.—Are obliged to go away!<br></br> Yet lest you find in this general combination of circumstances some sinister threat of audacity, let me conventionalize the story at once by opening it at that most conventional of all conventional Christmas-story hours,—the Twilight of Christmas Eve." (excerpt from the text)

5Molly Make-Believe

By Eleanor Hallowell Abbott

Carl Stanton is an invalid suffering from an unusual bout of rheumatism. His fiancee is gone for the winter and though he begs her to write to help ease his boredom and pain she is stingy with her letters. She sends him what she calls a 'ridiculous circular' which she states is very apropos of his sentimental passion for letters. In a sudden fit of mischief, malice and rheumatism, Carl decides to respond to the circular which results in bringing about the necessary distraction in a flurry of letters that do ease Carl's boredom and pain but also bring him something else that he never quite expected. (summary by Kehinde)

6Indiscreet Letter

By Eleanor Hallowell Abbott

Three fellow travelers on a train enter into a discussion concerning what they would call an 'indiscreet letter.' The discussion, albeit short, produces some rather interesting revelations during the journey and at journey's end. (Summary by Kehinde)

7Seven Wives and Seven Prisons; Or, Experiences in the Life of a Matrimonial Monomaniac

By L. A. Abbott

This work the author claims is indeed a true story of how he happened to be married seven times to seven different women and the rollicking, hilarious events that led (or stumbled) to the marriages and the ah--disassembling/failing/failures of each said marriage which happened oftentimes to land him in prison. The summarist finds the work a very tongue-in-cheek diatribe/lament/account of his obsessive zeal in 'marrying the right one', but is also the mirthful chronicle of said author's very unconventional adventures. (Summary by Kehinde)

8White Linen Nurse

By Eleanor Hallowell Abbott

The White Linen Nurse is a hysterical story of an exhausted nurse who comes to regret her profession and then somehow finds herself caring for the invalid daughter of the Senior Surgeon. The unexpected events which lead her there and also those which take her forward from that point are sure to evoke laughter and tears - a never to be forgotten story that will send a warm glow to your heart. (Summary by Kehinde)

9Cleopatra

By Jacob Abbott

A biography of the famous Cleopatra of Egypt, written in a manner, equally interesting to children and to adults.

<i>Flatland: A Romance of Many Dimensions</i> is an 1884 science fiction novella by the English schoolmaster Edwin Abbott Abbott. As a satire, <i>Flatland</i> offered pointed observations on the social hierarchy of Victorian culture. However, the novella's more enduring contribution is its examination of dimensions; in a foreword to one of the many publications of the novella, noted science writer Isaac Asimov described <i>Flatland</i> as "The best introduction one can find into the manner of perceiving dimensions." As such, the novella is still popular amongst mathematics, physics and computer science students. (Summary by Wikipedia)

There are certain names which are familiar, as names, to all mankind; and every person who seeks for any degree of mental cultivation, feels desirous of informing himself of the leading outlines of their history, that he may know, in brief, what it was in their characters or their doings which has given them so widely-extended a fame. Consequently, great historical names alone are selected; and it has been the writer's aim to present the prominent and leading traits in their characters, and all the important events in their lives, in a bold and free manner, and yet in the plain and simple language which is so obviously required in works which aim at permanent and practical usefulness. This volume is dedicated to William the Conqueror. (Summary from the preface of the book)

There are certain names which are familiar, as names, to all mankind; and every person who seeks for any degree of mental cultivation, feels desirous of informing himself of the leading outlines of their history, that he may know, in brief, what it was in their characters or their doings which has given them so widely-extended a fame. Consequently, great historical names alone are selected; and it has been the writer's aim to present the prominent and leading traits in their characters, and all the important events in their lives, in a bold and free manner, and yet in the plain and simple language which is so obviously required in works which aim at permanent and practical usefulness. This volume is dedicated to Queen Elizabeth. (Summary from the preface of the book)

There are certain names which are familiar, as names, to all mankind; and every person who seeks for any degree of mental cultivation, feels desirous of informing himself of the leading outlines of their history, that he may know, in brief, what it was in their characters or their doings which has given them so widely-extended a fame. Consequently, great historical names alone are selected; and it has been the writer's aim to present the prominent and leading traits in their characters, and all the important events in their lives, in a bold and free manner, and yet in the plain and simple language which is so obviously required in works which aim at permanent and practical usefulness. This volume is dedicated to Richard I. (Summary from the preface of the book)

There are certain names which are familiar, as names, to all mankind; and every person who seeks for any degree of mental cultivation, feels desirous of informing himself of the leading outlines of their history, that he may know, in brief, what it was in their characters or their doings which has given them so widely-extended a fame. Consequently, great historical names alone are selected; and it has been the writer's aim to present the prominent and leading traits in their characters, and all the important events in their lives, in a bold and free manner, and yet in the plain and simple language which is so obviously required in works which aim at permanent and practical usefulness. This volume is dedicated to Mary Queen of Scots. (Summary from the preface of the book)

There are certain names which are familiar, as names, to all mankind; and every person who seeks for any degree of mental cultivation, feels desirous of informing himself of the leading outlines of their history, that he may know, in brief, what it was in their characters or their doings which has given them so widely-extended a fame. Consequently, great historical names alone are selected; and it has been the writer's aim to present the prominent and leading traits in their characters, and all the important events in their lives, in a bold and free manner, and yet in the plain and simple language which is so obviously required in works which aim at permanent and practical usefulness. This volume is dedicated to Charles I. (Summary from the preface of the book)

There are certain names which are familiar, as names, to all mankind; and every person who seeks for any degree of mental cultivation, feels desirous of informing himself of the leading outlines of their history, that he may know, in brief, what it was in their characters or their doings which has given them so widely-extended a fame. Consequently, great historical names alone are selected; and it has been the writer's aim to present the prominent and leading traits in their characters, and all the important events in their lives, in a bold and free manner, and yet in the plain and simple language which is so obviously required in works which aim at permanent and practical usefulness. This volume is dedicated to Hannibal. (Summary from the preface of the book)

17Daniel Boone

By John Stevens Cabot Abbott

This is a detailed biography of the life and adventures of Daniel Boone. His accomplishments are brushed over in history classes these days and not given the recognition they deserve. This biography clearly paints a picture of the benevolent person of Daniel Boone as well as the achievements he made in furthering European settlement in America. (Summary by Allyson Hester)

Throughout three years of school, Rae Malgregor had been perfectly pliant, perfectly compliant to all the demands placed on her. But now, on the eve of graduation, she couldn’t go on with the mask of artificiality and the air of perfection. She had been chasing this nursing job three whole years, but there was just no wag to it! The Superintendent was stunned. Her best student! The Senior Surgeon was all grey granite business and livid that his time was being taken up with a hysterical nurse! And yet, though he wouldn’t have admitted it to anyone, especially himself, his interest was piqued. (Introduction by MaryAnn)

19Romulus

By Jacob Abbott

Jacob Abbott wrote many historical books for children. He was careful to ensure historical accuracy, and as he said himself in the preface to this book "Whatever of interest ... these stories may possess is due solely to the facts themselves which are recorded in them, and to their being brought together in a plain, simple, and connected narrative."<br /><br />This is the story of Romulus, the founding of Rome and the early years of its history, written in a way both readable and enjoyable for adults and children alike. (Summary by Ruth Golding)

20History of Julius Caesar

By Jacob Abbott

The book chronicles the extraordinary life and leadership of Rome’s Emperor Julius Caesar, from his early years to his assassination. (Summary by Cathy Barratt)

21Richard III (Makers of History series)

By Jacob Abbott

Jacob Abbott chronicles the unspeakably treacherous rise of Richard III to the throne of England in the midst of the war between the Yorks and the Lancasters and his ultimate fall on the Field of Bosworth. (Introduction by Cathy Barratt)