Downloads & Free Reading Options - Results

In aerospace computational fluid dynamics (CFD) calculations, the Delaunay triangulation of suitable quadrilateral meshes can lead to unsuitable triangulated meshes. Here, we present case studies which illustrate the limitations of using structured grid generation methods which produce points in a curvilinear coordinate system for subsequent triangulations for CFD applications. We discuss conditions under which meshes of quadrilateral elements may not produce a Delaunay triangulation suitable for CFD calculations, particularly with regard to high aspect ratio, skewed quadrilateral elements.

Computational fluid dynamics (CFD) has made great strides in the detailed simulation of complex fluid flows, including the fluid physics of flows heretofore not understood. It is now being routinely applied to some rather complicated problems, and starting to impact the design cycle of aerospace vehicles and their components. In addition, it is being used to complement and is being complemented by experimental studies. In this paper some major elements of contemporary CFD research, such as code validation, turbulence physics, and hypersonic flows are discussed, along with a review of the principal pacing items that currently govern CFD. Several examples are presented to illustrate the current state of the art. Finally, prospects for the future of the development and application of CFD are suggested.

Automation of flow field zoning in two dimensions is an important step towards reducing the difficulty of three-dimensional grid generation in computational fluid dynamics. Using a knowledge-based approach makes sense, but problems arise which are caused by aspects of zoning involving perception, lack of expert consensus, and design processes. These obstacles are overcome by means of a simple shape and configuration language, a tunable zoning archetype, and a method of assembling plans from selected, predefined subplans. A demonstration system for knowledge-based two-dimensional flow field zoning has been successfully implemented and tested on representative aerodynamic configurations. The results show that this approach can produce flow field zonings that are acceptable to experts with differing evaluation criteria.

Automation of flow field zoning in two dimensions is an important step towards reducing the difficulty of three-dimensional grid generation in computational fluid dynamics. Using a knowledge-based approach makes sense, but problems arise which are caused by aspects of zoning involving perception, lack of expert consensus, and design processes. These obstacles are overcome by means of a simple shape and configuration language, a tunable zoning archetype, and a method of assembling plans from selected, predefined subplans. A demonstration system for knowledge-based two-dimensional flow field zoning has been successfully implemented and tested on representative aerodynamic configurations. The results show that this approach can produce flow field zonings that are acceptable to experts with differing evaluation criteria.

Lately with the headway of thermo electric materials, direct change of warmth vitality into electrical vitality gets conceivable. Thermoelectric innovation is utilized for recuperating heat vitality loses from motor fumes gases. The force produced by thermoelectric innovation is called as thermoelectric force. In thermo electric force age a fumes heat exchanger is utilized for recouping exhaust heat and a thermo electric module is utilized for changing over warmth into power. The current examination was expected to improve the structure of fumes heat exchanger by expelling inside blades and changing the cross sectional region of warmth exchanger to conquer issue of weight drop. The structures of fumes heat exchangers considered in the past exploration works recouped most extreme warmth from the fumes of a motor However issue of weight drop or back weight was watched affecting motor execution and working. Higher back weight can break down and harm motor bringing about stoppage of motor working. Computational liquid elements CFD was utilized in the recreation of the fumes gases streaming inside the warmth exchanger. The isothermal displaying strategy was utilized in recreation procedure of the warmth exchanger. The warm reenactment is done on heat exchanger to check the surface temperature, heat move rate, and weight drop in three distinctive test conditions urban driving, rural driving and max. power driving of a vehicle with 1.2 L petroleum motor. Rectangular molded warmth exchanger was utilized in ventilation system of interior burning motor ICE is demonstrated numerically to recoup the lost warmth from motor fumes. The examination uncovered that Rectangular molded warmth exchanger with progressively expanding cross sectional region limited weight drop and achieves higher temperature and warmth move rate at the surface. The mean surface temperatures acquired after CFD examination are 459K, 555K, and 791K for the three test conditions. The weight drop for the three test conditions are 24.14 Pa, 182.5 Pa and 5.413 Kpa and that is inside as far as possible. Abhimanyu Pal | N. V. Saxena "Computational Fluid Dynamics Analysis of Exhaust Heat Exchanger for TED" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-5 , August 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33006.pdf Paper Url :https://www.ijtsrd.com/engineering/mechanical-engineering/33006/computational-fluid-dynamics-analysis-of-exhaust-heat-exchanger-for-ted/abhimanyu-pal

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

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

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

A Computational Fluid Dynamics (CFD) analysis was performed on a C-135 aircraft with a side-mounted splitter plate at the request of the Airborne Laser SPO at Kirtland AFB, and the 4950 Test Wing at Wright-Patterson AFB. The data collected from the analysis was provided to the Test Wing to augment wind tunnel tests and to provide loading and stability information on the modified aircraft. This work was a precursor to a planned flight test program in which a splitter plate will be tested on a Test Wing aircraft. Four flight conditions were analyzed with a modified and unmodified C-135 aerodynamic model, and incremental stability and aerodynamic derivatives were determined. Additionally, pressure coefficient data were tabulated for use in a structural analysis by the Test Wing. (AN)

Research on both internal and free-surface flows related to experimental situations was continued. Part of this research was based on using a low-order code developed previously, jointly by Pritchard and Scott. Funds for the programmer allowed two substantial new programming projects to be initiated during this time. One concerned investigation of techniques for implementing a quartic finite element method for viscous, incompressible, two-dimensional flows. The other involved a streamline-diffusion finite element method for inviscid flows.

This research project has developed methods for computational fluid dynamics and fluid-flow control. The research on computational fluid dynamics has consisted of the analysis and development of simulations and mathematical models of two-dimensional fluid motion. The control research has used a hierarchy of simulations and models t design feedback controllers for fluid flows. Both adaptive and nonadaptive controllers were developed. The research was motivated by the need to stabilize high Reynolds number flows around bodies such as delta wing aircraft.

CFD is a software application that helps end-users analyze the flow, turbulence, and pressure distribution of liquids and gases, and their interaction with structures. It also helps in predicting fluid flow, mass transfer, chemical reactions, and related phenomena. CFD uses high-speed computers, and various numerical methods and solvers to simulate the flow of fluids (gases and liquids). Simulation refers to the digital prototype of the real-world scenario. This helps detect errors in design before proceeding to production. CFD finds wide ranging applications in industries such as automotive, aerospace and defense, electrical and electronics, and energy. CFDs are used to design fuel systems, engine core compartments, cockpit and cabin ventilation, missiles, submarines, and evaluate aerodynamics in the aerospace and defense industry.

The grant supported a symposium on Computational Fluid Dynamics held at Half Moon Bay, California, June 26-28, 2000. The symposium consisted of three days of technical sessions on: (1) Theory of High Speed Flows; (2) Algorithm Development and Computational Techniques; and (3) Applications in Aeronautics and Beyond (i.e., Electromagnetics, Magnetohydrodynamics, etc.). The symposium assembled the leading researchers in these fields and several distinguished scholars were invited to present their work. The goal was to present the state of the art with emphasis placed on new directions and practical applications in industry. With no parallel sessions, there was sufficient time for discussion and interaction between the participants.

The grant supported a symposium on Computational Fluid Dynamics held at Half Moon Bay, California, June 26-28, 2000. The symposium consisted of three days of technical sessions on: (1) Theory of High Speed Flows; (2) Algorithm Development and Computational Techniques; and (3) Applications in Aeronautics and Beyond (i.e., Electromagnetics, Magnetohydrodynamics, etc.). The symposium assembled the leading researchers in these fields and several distinguished scholars were invited to present their work. The goal was to present the state of the art with emphasis placed on new directions and practical applications in industry. With no parallel sessions, there was sufficient time for discussion and interaction between the participants.

The computational science community is reluctant to write large-scale computationally -intensive applications in Java due to concerns over Java's poor performance, despite the claimed software engineering advantages of its object-oriented features. Naive Java implementations of numerical algorithms can perform poorly compared to corresponding Fortran or C implementations. To achieve high performance, Java applications must be designed with good performance as a primary goal. This paper presents the object-oriented design and implementation of two real-world applications from the field of Computational Fluid Dynamics (CFD): a finite-volume fluid flow solver (LAURA, from NASA Langley Research Center), and an unstructured mesh adaptation algorithm (2D_TAG, from NASA Ames Research Center). This work builds on our previous experience with the design of high-performance numerical libraries in Java. We examine the performance of the applications using the currently available Java infrastructure and show that the Java version of the flow solver LAURA performs almost within a factor of 2 of the original procedural version. Our Java version of the mesh adaptation algorithm 2D_TAG performs within a factor of 1.5 of its original procedural version on certain platforms. Our results demonstrate that object-oriented software design principles are not necessarily inimical to high performance.

Early experimental work, conducted at Defence R and D Canada Suffield, measured and characterized the personal and environmental contamination associated with simulated anthrax-tainted letters under a number of different scenarios in order to obtain a better understanding of the physical and biological processes for detecting, assessing, and formulating potential mitigation strategies for managing the risks associated with opening an anthrax-tainted letter. These preliminary experimental investigations have been extended in the present study to simulate the contamination from anthrax-tainted letters in an Open-Office environment using Computational Fluid Dynamics (CFD). A quantity of 0.1 g of a biological simulant Bacillus globigii (BG) for anthrax was released from an opened letter in the experiment. The accuracy of the model for prediction of the spatial distribution of BG spores in the office from the opened letter is assessed qualitatively (and to the extent possible, quantitatively) by detailed comparison with measured BG concentrations obtained under a number of scenarios, some involving people moving within the office. It is hypothesized that the discrepancy between the numerical predictions and experimental measurements of concentration were mainly caused by :(1) air flow leakage from cracks and crevices in the walls and windows of the building shell; (2) decoupling between the present CFD simulation and dispersion of BG spores in the Heating, Ventilation, and Air Conditioning (HVAC) system; (3) the effect of deposition and re-suspension of BG spores not being considered in the present CFD simulations. Although there is still a scope of further improvement in the present CFD simulation, it should be emphasized here that the advantages of utilization of CFD modeling for assessment and design of mitigation strategies and protocols for defence against anthrax-tainted letters over an experimentally based approach to the problem are obvious:

This research concerned three independent projects of ICMA (Institute of Computational Mathematics and Applications) personnel, each belonging to the general area of computational fluid dynamics. The first project dealt with the computation of stationary Navier-Stokes solutions using continuation methods. Error estimates for certain finite element solutions of continuation problems were derived and extensions to more general operators including the Navier-Stokes operator were investigated. Numerical methods for the detection of Hopf bifurcation were studied. The second project involved construction, analysis and implementation of efficient computer algorithms for the finite difference and finite element-dual variable discretization of the two-dimensional Navier-Stokes problems. Particular attention was given to finite element and finite differences discretization such problems that arise in combustor modeling. The third project sought to extend the dual variable reduction technique to various fluid models. This required the construction of a network analogue for the discrete difference equations along with an analysis of the fundamental matrix and dual variable transformation involved. (Author)

The propagation characteristics of several helicopter airfoil profiles have been investigated using the transonic small disturbance equation. A test case was performed to generate a moving shock that propagated off the airfoil. Various grids were then examined to determine their ability to accurately capture these propagating shock waves. Finally, the case of airfoil vortex interactions was thoroughly studied over a wide range of Mach numbers and airfoil shapes with particular emphasis on the transonic regime; this results in a highly complicated fluctuation of lift, drag, and pitching moment. The calculated acoustic intensity levels, along with the details of the computational flow field, provide new insights into the understanding of transonic airfoil vortex interactions.

Research is directed at the application of modern computer technologies, with emphasis on emerging parallel computing techniques to the solution of fluid dynamic problems. CFD algorithms will be developed, implemented, analyzed and benchmarked on several different architecture parallel computers. Keywords: Parallel processing, Algorithms, Domain decomposition.

Dynamic mesh adaptation strategies are investigated. These include software development, dynamically adaptive mesh schemes, errors arising from generalized mappings and orthogonality. The strategies developed are tested against the euler and viscous Burgers Equations.

The overall goal of this research was the development and application of covolume methodology in CFD and related areas. The main framework of the covolume approach is now in place and its major characteristics are reasonably well understood. The research shows the algorithm to be a stable and accurate approach to computing viscous fluids on unstructured meshes. The covolume approach has several unique features, including an associated discrete vector field theory, which in turn permits covolume discretizations to exhibit important physical characteristics, for example being free of artificial vorticity creation. There is still need for work in compressible and three dimensional flows.

Algorithm development. Implementation of a 3-D Navier Stokes implicit research code for AFFDL was initiated. This required the parallel solution of block-tridiagonal system and so was more challenging than the above explicit code. This is being continued in a new AFOSR grant. Connection Machine experiments. To keep abreast of SIMD architecture performance, a series of Fortran and C kerrels were studies on the Argonne Laboratory CM-2 during the summer of 1989. It was concluded that the available Fortran 8X implementation of the CM-2 was too inefficient to warrant continued at that time. Keywords: Programming languages; Computer programming; Computer architecture.

This research concerns projects of seven investigators at the University of Pittsburgh relating to the general area of computational fluid dynamics. Topics include the dual variable method, Differential Algebraic Equation, the reduced basis method, divergence free finite elements, diffusive- transport systems, and bifurcation phenomena. Short descriptions of these projects are included, along with references to published reports. (jg)

Analytical methods and computational fluid dynamics are used to describe flow conditions encountered at Naval Research Laboratory's Ballast Water Treatment Test Facility. Design tradeoffs are examined in the engineering of sample ports for collecting biological organisms in water samples, and criteria are provided for sample port installation in shipboard piping systems. Results of this work show that the ideal geometry for biological sampling is from the centerline of a straight, vertical, upward-flowing pipe having a sample port diameter between 1.5 and 2.0 times the basic isokinetic diameter as defined in this report. Sample ports should use ball valves for isolation purposes, and diaphragm or venturi valves for flow control; they should be located as close to the overboard outlet as possible; and they should be positioned as far from upstream obstructions and fittings as possible.

The objectives of this program were to: validate CFD-based OPD model using wavefront sensor data from wind tunnel experiments; exercise CFD model to assess performance of larger, more realistic configuration with conformal window; and determine wavefront control system requirements. CFD validation consisted of: wind tunnel WFS measurements of phase over scaled turret with conformal window; and comparison with CFD-based model at 1:1 scale including wind tunnel boundaries and inlet flow profile. Large scale analysis entailed assessing performance of larger turret with conformal window, and evaluating wavefront control requirements. The program was successfully completed. Turrets were designed and fabricated; wind tunnel tests were conducted; WFS data was collected; the CFD-based aero model was validated; and large scale analysis and wavefront control requirements were completed.

This report describes an overview of the research efforts undertaken to develop a computational fluid dynamics (CFD) tool to analyze flow fields relevant to chemical oxygen/iodine lasers (COIL). In the listed references, computations of the three-dimensional nozzle flow fields with transverse jet injection are described in addition to several two-dimensional computational results, verifying the implementation of the model equations. Improvement in the efficiency of the computations was demonstrated by the use of a grid sequencing approach. (7 refs.)

The Final Proceedings for Parallel Computational Fluid Dynamics (CFD) Workshop, 16 June 1999 - 18 June 1999. This is an interdisciplinary conference. Topics to include: Turbulent Flows; Multiphysics Flows; Aerodynamic Flows; Multidisciplinary Applications; Parallel Computing in Aerospace and Mechanical Engineering; Parallel and Sequential Grid Partitioning Techniques; Parallel Grid Generation; Load Balancing; Domain Decomposition, etc.

High-order space-time methods for Computational Fluid Dynamics are studied. Both explicit and implicit schemes will be discussed

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.

-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-

Introduction Large industrial factories often discharge significant quantities of low-pressure steam (dead steam) into the atmosphere, which causes energy losses. Retaining low-pressure steam content reduces boiler load, resulting in energy savings and lower costs for the fuel consumption (for example, gas consumption bill in a factory). The boosted-pressure steam is used in processes such as distillation, hot water production, space heating or vacuum generation. If the vapor pressure for the intended application is low, a thermo-compressor is able to increase the pressure and temperature to the required level. Thermo-compressors are a special type of gas compressor that uses an actuator to compress secondary fluid and does not have any blades or moving parts. The accurate prediction of the thermo-compressor performance improves the reliability of this process and increases its efficiency. Materials and Methods Two important characteristics for the current thermo-compressors are entrainment ratio (ER) and compression ratio (CR). The first is the dimensionless mass flow rate, and the second is the dimensionless pressure. The wet steam theory as a classic theory is used by Wolmer-Frankel-Zeldovich to calculate the amount of liquid particles. In order to select the best geometry for the thermo-compressor among all possible geometries, the performance of each model must be compared with other models. In following, the case that includes characteristic parameters associated with the target values has been selected. The commercial Ansys Fluent Versions 15, based on the finite volume method (FVM) was used to simulate and monitoring the flow behavior inside the thermo-compressor. The governing partial differential equations (PDE) were solved implicitly using a density-based solution. The convective heat transfer terms were discriminated based on the second-order upwind scheme. The non-linear governing equations were solved using the implicit coupling solver and the standard wall function was used near the wall. Given the three-dimensional flow for steam, the equations of mass conservation, momentum, and energy were written. The Realizable  model was used to simulate turbulences in the flow. Results and Discussion A summary of the results is presented in terms of the results of pressure, velocity magnitude, Mach number and temperature. A general understanding of this characteristic for a thermo-compressor is extremely important for recognizing the fluid flow inside it, and it is very useful for practical use. Pressure is the most important factor in the recharge section of a thermo-compressor. Increasing the recharge vapor pressure in a thermos-compressor revival the dead steam and increases the steam efficiency. The revival steam can be used in other parts because of their high thermal content. Another important factor in the study of flow behavior inside the thermocouple is velocity magnitude. This quantity, which is closely related to the concept of momentum inside the thermocouple, had high influences from high pressure inputs as well as the thermo-compressor geometry. The highest amount of velocity occurs after the initial nozzle and had a very high magnitude (1000 ms -1 ), which was also remarkably high in Monnet's terms. Another important characteristic of a flow is the temperature of the stream. The high input temperature associated with motive vapor at the outlet of the primary nozzle was sharply reduced, even in some section reached to 110 °Kelvin. Due to the very high flow momentum in this section, the fluid phase remained gas and it can be justified from the point of view of the fluid dynamics. Conclusion Considering the importance of thermodynamic properties of steam in conversion and industries, it would be extremely beneficial to fully understand the interactions inside the thermocouple compressor. The importance of the discussed characteristics is more specific when there is a close relationship between each of these factors and energy consumption in a factory or in any industrial production unit. It was observed that the designed thermos-compressor was able to increase the velocity and temperature in a desirable range for the conversion of non-consumable vapor to the pressure and temperature. It was concluded that the Realizable  model due to the prediction of the jet characteristics appearing in the flow regimes for axial symmetry had a high ability to simulate fluid flows inside the thermos-compressor.

One of NASA's objectives is to be able to perform a complete, pre-flight, evaluation of cardiovascular changes in astronauts scheduled for prolonged space missions. Computational fluid dynamics (CFD) has shown promise as a method for estimating cardiovascular function during reduced gravity conditions. For this purpose, MRI can provide geometrical information, to reconstruct vessel geometries, and measure all spatial velocity components, providing location specific boundary conditions. The objective of this study was to investigate the reliability of MRI-based model reconstruction and measured boundary conditions for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T Siemens MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction (slice thickness 3 and 5 mm; pixel size 1x1 and 0.5x0.5 square millimeters). Velocity acquisitions provided measured inlet boundary conditions and localized three-directional steady-flow velocity data (0.7-3.0 L/min). The vessel walls were isolated using NIH provided software (ImageJ) and lofted to form the geometric surface. Constructed and idealized geometries were imported into a commercial CFD code for meshing and simulation. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with less than 10% differences in the local velocity values. CFD results on models reconstructed from different MRI resolution settings showed insignificant differences (less than 5%). This study illustrated, quantitatively, that reliable CFD simulations can be performed with MRI reconstructed models and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system alteration during space travel is feasible.

The application and assessment of the recently developed CAP-TSD transonic small-disturbance code for flutter prediction is described. The CAP-TSD code has been developed for aeroelastic analysis of complete aircraft configurations and was previously applied to the calculation of steady and unsteady pressures with favorable results. Generalized aerodynamic forces and flutter characteristics are calculated and compared with linear theory results and with experimental data for a 45 deg sweptback wing. These results are in good agreement with the experimental flutter data which is the first step toward validating CAP-TSD for general transonic aeroelastic applications. The paper presents these results and comparisons along with general remarks regarding modern wing flutter analysis by computational fluid dynamics methods.

The present study demonstrates that the Reduced Navier-Stokes code RNS3D can be used very effectively to develop a vortex generator installation for the purpose of minimizing the engine face circumferential distortion by controlling the development of secondary flow. The computing times required are small enough that studies such as this are feasible within an analysis-design environment with all its constraints of time and costs. This research study also established the nature of the performance improvements that can be realized with vortex flow control, and suggests a set of aerodynamic properties (called observations) that can be used to arrive at a successful vortex generator installation design. The ultimate aim of this research is to manage inlet distortion by controlling secondary flow through an arrangements of vortex generators configurations tailored to the specific aerodynamic characteristics of the inlet duct. This study also indicated that scaling between flight and typical wind tunnel test conditions is possible only within a very narrow range of generator configurations close to an optimum installation. This paper also suggests a possible law that can be used to scale generator blade height for experimental testing, but further research in this area is needed before it can be effectively applied to practical problems. Lastly, this study indicated that vortex generator installation design for inlet ducts is more complex than simply satisfying the requirement of attached flow, it must satisfy the requirement of minimum engine face distortion.

The present study demonstrates that the Reduced Navier-Stokes code RNS3D can be used very effectively to develop a vortex generator installation for the purpose of minimizing the engine face circumferential distortion by controlling the development of secondary flow. The computing times required are small enough that studies such as this are feasible within an analysis-design environment with all its constraints of time and costs. This research study also established the nature of the performance improvements that can be realized with vortex flow control, and suggests a set of aerodynamic properties (called observations) that can be used to arrive at a successful vortex generator installation design. The ultimate aim of this research is to manage inlet distortion by controlling secondary flow through an arrangements of vortex generators configurations tailored to the specific aerodynamic characteristics of the inlet duct. This study also indicated that scaling between flight and typical wind tunnel test conditions is possible only within a very narrow range of generator configurations close to an optimum installation. This paper also suggests a possible law that can be used to scale generator blade height for experimental testing, but further research in this area is needed before it can be effectively applied to practical problems. Lastly, this study indicated that vortex generator installation design for inlet ducts is more complex than simply satisfying the requirement of attached flow, it must satisfy the requirement of minimum engine face distortion.

The present study demonstrates that the Reduced Navier-Stokes code RNS3D can be used very effectively to develop a vortex generator installation for the purpose of minimizing the engine face circumferential distortion by controlling the development of secondary flow. The computing times required are small enough that studies such as this are feasible within an analysis-design environment with all its constraints of time and costs. This research study also established the nature of the performance improvements that can be realized with vortex flow control, and suggests a set of aerodynamic properties (called observations) that can be used to arrive at a successful vortex generator installation design. The ultimate aim of this research is to manage inlet distortion by controlling secondary flow through an arrangements of vortex generators configurations tailored to the specific aerodynamic characteristics of the inlet duct. This study also indicated that scaling between flight and typical wind tunnel test conditions is possible only within a very narrow range of generator configurations close to an optimum installation. This paper also suggests a possible law that can be used to scale generator blade height for experimental testing, but further research in this area is needed before it can be effectively applied to practical problems. Lastly, this study indicated that vortex generator installation design for inlet ducts is more complex than simply satisfying the requirement of attached flow, it must satisfy the requirement of minimum engine face distortion.

The present study demonstrates that the Reduced Navier-Stokes code RNS3D can be used very effectively to develop a vortex generator installation for the purpose of minimizing the engine face circumferential distortion by controlling the development of secondary flow. The computing times required are small enough that studies such as this are feasible within an analysis-design environment with all its constraints of time and costs. This research study also established the nature of the performance improvements that can be realized with vortex flow control, and suggests a set of aerodynamic properties (called observations) that can be used to arrive at a successful vortex generator installation design. The ultimate aim of this research is to manage inlet distortion by controlling secondary flow through an arrangements of vortex generators configurations tailored to the specific aerodynamic characteristics of the inlet duct. This study also indicated that scaling between flight and typical wind tunnel test conditions is possible only within a very narrow range of generator configurations close to an optimum installation. This paper also suggests a possible law that can be used to scale generator blade height for experimental testing, but further research in this area is needed before it can be effectively applied to practical problems. Lastly, this study indicated that vortex generator installation design for inlet ducts is more complex than simply satisfying the requirement of attached flow, it must satisfy the requirement of minimum engine face distortion.

The main objective of this present investigation is to design and analyse pump impeller to give better performance than the existing once. Designing impellers are important for fluid flow analysis for a pump. The impeller of an existing industrial pump was analysed and redesigned using an integrated, design/analysis, turbo machinery geometry modelling and flow simulation system. The purpose of the redesign was to achieve improved impeller performance. To improve the efficiency of pump, computational fluid dynamics (CFD) analysis is one which is used in the pump industry. In the present model Acrylonitrile butadiene styrene (ABS) material is used to reduce noise and cutting down the cost of the impeller. The number of impeller blades is proposed to increase from 6-8 to 16 in order to increase fluid velocity. Inlet blade angle is reduced to less than 35 degrees from greater than 55 degrees to increase efficiency and outlet fluid velocity of the impeller. From the CFD analysis to calculate the efficiency of the existing impeller by using the empirical relations. In the first case outlet angle is increased, and in the second case inlet angle is decreased and they are obtained from the CFD analysis. 

The main objective of this present investigation is to design and analyse pump impeller to give better performance than the existing once. Designing impellers are important for fluid flow analysis for a pump. The impeller of an existing industrial pump was analysed and redesigned using an integrated, design/analysis, turbo machinery geometry modelling and flow simulation system. The purpose of the redesign was to achieve improved impeller performance. To improve the efficiency of pump, computational fluid dynamics (CFD) analysis is one which is used in the pump industry. In the present model Acrylonitrile butadiene styrene (ABS) material is used to reduce noise and cutting down the cost of the impeller. The number of impeller blades is proposed to increase from 6-8 to 16 in order to increase fluid velocity. Inlet blade angle is reduced to less than 35 degrees from greater than 55 degrees to increase efficiency and outlet fluid velocity of the impeller. From the CFD analysis to calculate the efficiency of the existing impeller by using the empirical relations. In the first case outlet angle is increased, and in the second case inlet angle is decreased and they are obtained from the CFD analysis. 

The main objective of this present investigation is to design and analyse pump impeller to give better performance than the existing once. Designing impellers are important for fluid flow analysis for a pump. The impeller of an existing industrial pump was analysed and redesigned using an integrated, design/analysis, turbo machinery geometry modelling and flow simulation system. The purpose of the redesign was to achieve improved impeller performance. To improve the efficiency of pump, computational fluid dynamics (CFD) analysis is one which is used in the pump industry. In the present model Acrylonitrile butadiene styrene (ABS) material is used to reduce noise and cutting down the cost of the impeller. The number of impeller blades is proposed to increase from 6-8 to 16 in order to increase fluid velocity. Inlet blade angle is reduced to less than 35 degrees from greater than 55 degrees to increase efficiency and outlet fluid velocity of the impeller. From the CFD analysis to calculate the efficiency of the existing impeller by using the empirical relations. In the first case outlet angle is increased, and in the second case inlet angle is decreased and they are obtained from the CFD analysis. 

The main objective of this present investigation is to design and analyse pump impeller to give better performance than the existing once. Designing impellers are important for fluid flow analysis for a pump. The impeller of an existing industrial pump was analysed and redesigned using an integrated, design/analysis, turbo machinery geometry modelling and flow simulation system. The purpose of the redesign was to achieve improved impeller performance. To improve the efficiency of pump, computational fluid dynamics (CFD) analysis is one which is used in the pump industry. In the present model Acrylonitrile butadiene styrene (ABS) material is used to reduce noise and cutting down the cost of the impeller. The number of impeller blades is proposed to increase from 6-8 to 16 in order to increase fluid velocity. Inlet blade angle is reduced to less than 35 degrees from greater than 55 degrees to increase efficiency and outlet fluid velocity of the impeller. From the CFD analysis to calculate the efficiency of the existing impeller by using the empirical relations. In the first case outlet angle is increased, and in the second case inlet angle is decreased and they are obtained from the CFD analysis. 

The main objective of this present investigation is to design and analyse pump impeller to give better performance than the existing once. Designing impellers are important for fluid flow analysis for a pump. The impeller of an existing industrial pump was analysed and redesigned using an integrated, design/analysis, turbo machinery geometry modelling and flow simulation system. The purpose of the redesign was to achieve improved impeller performance. To improve the efficiency of pump, computational fluid dynamics (CFD) analysis is one which is used in the pump industry. In the present model Acrylonitrile butadiene styrene (ABS) material is used to reduce noise and cutting down the cost of the impeller. The number of impeller blades is proposed to increase from 6-8 to 16 in order to increase fluid velocity. Inlet blade angle is reduced to less than 35 degrees from greater than 55 degrees to increase efficiency and outlet fluid velocity of the impeller. From the CFD analysis to calculate the efficiency of the existing impeller by using the empirical relations. In the first case outlet angle is increased, and in the second case inlet angle is decreased and they are obtained from the CFD analysis. 

A study was conducted to evaluate the accuracy of a commercial computational fluid dynamics (CFD) code (CFDRC-ACE+) for predicting incompressible air jet flows with simple geometries. Specifically, the axis- symmetric and two-dimensional heated air-jets were simulated using a standard k- epsilon turbulence model. These CFD predictions were directly compared to an extensive compilation of experimental data from archive literature. The round jet results indicated that the code over-predicted the velocity-spreading rate by 24% and the temperature spreading rate by 29%

Using the commercially available FLUENT 3-D flow field solver, this research effort investigated vortex breakdown over a delta wing at high angle of attack (a) in preparation for investigation of active control of vortex breakdown using steady, along- core blowing A flat delta-shaped half-wing with sharp leading edge and sweep angle of 600 was modeled at a 180 in a wind tunnel at Mach 0,04 and Reynolds number of 3,4 x 10(sub 5). A hybrid (combination of structured and unstructured) numerical mesh was generated to accommodate blowing ports on the wing surface. Results for cases without and with along-core blowing included comparison of various turbulence models for predicting both flow field physics and quantitative flow characteristics, FLUENT turbulence models included Spalart-Allmaras (S-A), Renormalization Group k-e, Reynolds Stress (RSM), and Large Eddy Simulation (LES), as well as comparison with laminar and inviscid models. Mesh independence was also investigated, and solutions were compared with experimentally determined results and theoretical prediction, These research results show that, excepting the LES model for which the computational mesh was insufficiently refined and which was not extensively investigated, none of the turbulence models above, as implemented with the given numerical grid, generated a solution which was suitably comparable to the experimental data. Much more work is required to find a suitable combination of numerical grid and turbulence model.

Geometrical, flight, computational fluid dynamics (CFD), and wind-tunnel studies for the F-16XL-1 airplane are summarized over a wide range of test conditions. Details are as follows: (1) For geometry, the upper surface of the airplane and the numerical surface description compare reasonably well. (2) For flight, CFD, and wind-tunnel surface pressures, the comparisons are generally good at low angles of attack at both subsonic and transonic speeds, however, local differences are present. In addition, the shock location at transonic speeds from wind-tunnel pressure contours is near the aileron hinge line and generally is in correlative agreement with flight results. (3) For boundary layers, flight profiles were predicted reasonably well for attached flow and underneath the primary vortex but not for the secondary vortex. Flight data indicate the presence of an interaction of the secondary vortex system and the boundary layer and the boundary-layer measurements show the secondary vortex located more outboard than predicted. (4) Predicted and measured skin friction distributions showed qualitative agreement for a two vortex system. (5) Web-based data-extraction and computational-graphical tools have proven useful in expediting the preceding comparisons. (6) Data fusion has produced insightful results for a variety of visualization-based data sets.

In the photograph, the contour lines indicate temperature at Mach 19 around a generic vehicle similar to the X-30. Because of high pressure and skin friction, the temperature is highest on the surface of the model. The vivid blue color indicates temperature 18 times hotter than the atmosphere, requiring active cooling from within the aircraft to control temperature on the planes surface. Pink color on the outer rings is much cooler than the blue near the body, but is still 2 times hotter than the environment in which the plane travels.

A computer program for displaying flow-field color contour plots, generated from computational fluid dynamics (CFD) solutions, has been developed by extending the contour plotting option of the GENPLOT routine of Dr. R. G. Hindman. An algorithm for generating color-filled contour regions was developed for this extension and is described. The algorithm performs a detailed examination of the behavior of the dependent variable within the plotting domain to generate the contour regions and determines the relationship between these regions and their associated contour levels to assign the appropriate fill color to a particular region. Flow-field color contour plots generated from a hypersonic viscous shock-layer computation, a supersonic viscous blunt-fin computation, and a hypersonic viscous gas jet nosetip computation are presented to illustrate the capabilities and flexibility to the routine and to demonstrate that they can be used to aid the interpretation of CFD results.

The growing application of computational aerodynamics to nonlinear rotorcraft problems is outlined, with particular emphasis on the development of new methods based on Euler and thin-layer Navier-Stokes equations. Rotor airfoil characteristics can now be calculated accurately over a wide range of transonic flow conditions. However, unsteady three-dimensional viscous codes remain in the research stage, and a numerical simulation of the complete flow field about a helicopter in forward flight is not currently feasbile. Nevertheless, impressive progress is being made in preparation for future supercomputers that will enable meaningful calculations to be made for arbitrary rotorcraft configurations.

This report results from a contract tasking University of Glasgow as follows: The objective is to develop efficient CFD based techniques for the prediction of wing rock instabilities for a delta wing-body. Two approaches in addition to the basic time marching approach will be investigated. First direct calculation of the Hopf point for the onset of the instability (for a fixed sweep angle the incidence is regarded as the bifurcation parameter) will be developed based on techniques previously developed for aeroelasticity. Secondly reduced order models will be developed driven by CFD results to again predict the instability onset efficiently. Finally an assessment of the different methods will be carried out to provide guidance for future application in certification by analysis and design. The derived solutions will also be examined to answer some of the current questions as to the physical mechanisms for wing rock.

We comment on the current performance of computational fluid dynamics codes on a variety of scalable computer architectures. The performance figures are derived from both the finite volume and finite element methodologies, and encompass shared, virtual shared, and distributed memory architectures, as exemplified by the SGI Origin series, CM5, and the CRAY T3D/E family, respectively.