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Fluid mechanics

A Selection of Test Cases for the Validation of Large-Eddy Simulations of Turbulent Flows

This is Research and Technology Organization (RTO) AGARD Advisory Report, AGARD-AR-345, dated April 1998. It was sponsored by the Advisory Group for Aerospace Research and Development. The results of the AGARD FDP Working Group 21 on "A Selection of Test Cases for the Validation of Large Eddy Simulations of Turbulent Flows" are presented in this report. The data contained in the report consist of building-block experiments documented in as much detail as possible. They are useful for the validation of Reynolds Averaged modeling and for the preliminary evaluation of experiments or turbulence theories. They include both laboratory experiments and direct numerical simulations. The introductory chapters are complemented by data sheets which describe in detail each data set, the experimental or numerical procedures, the expected errors, and the initial and boundary conditions. The data are given in machine-readable form in the CD-ROM that accompanies the report. Bibliographic details and an abstract are available in HTML format and the full text is available in PDF format(6.5Mb)from the RTO's web site.

Aerodynamic Engine/Airframe Integration for High Performance Aircraft and Missiles

This is Research and Technology Organization (RTO) AGARD-CP-498, dated September 1992. The objective of the symposium was to review the state-of-the-art in aerodynamic engine/airframe integration techniques and to report on the progress which has been achieved during engineering project work in recent years. Because the treatment of this subject requires an interdisciplinary approach, both experimentalists and theoreticians were invited to contribute to the meeting. Six sessions were organized to cover the essential subdisciplines requiring aerodynamic engine/airframe integration during the concept-assessment and design phases for new aerospace vehicles. For individual titles, see N93-13200 through N93-13231. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (** MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Aerodynamics and Acoustics of Propellers

This is Research and Technology Organization (RTO) AGARD-CP-366, dated February 1985. A state of the art review of the aerodynamic design and testing of modern propellers, acoustic and vibration environmental problems and their solutions, and considerations in the integration of the propeller(s) and airframe is presented. Propellers have recently become a focus of attention after having been neglected for many years. The efficient use of propellers as a propulsion medium up to Mach 0.6 was realized at the expense of high noise and vibration. Since the mid-1970s there have been many developments, including the propfan, with an aerodynamic efficiency of 80% at Mach 0.8 now seriously challenges the fanjet. The advent of the supercritical airfoil is another significant development beginning to influence propeller design. For individual titles see N86-11148 through N86-11176. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (66.77MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Aerospace-Related Fluid Physics, Heat Transfer, and Thermal Control Research at the NLR Space Division

This technical report (NLR-TP-2001-300) was published by NLR (the National Aerospace Laboratory of the Netherlands) in 2001 and was written by A. A. M. Dell. Including the information published earlier [1], the aerospace-related fluid physics, heat transfer and thermal control research carried out by the NLR Space Division can be summarised by: - Thermal conductivity investigations. - Design and manufacture of a test rig for measuring the thermal conductance of axially loaded rotating bearings in vacuum. - Thermal modelling of various rotating space mechanisms and the compilation of a handbook to model such mechanisms. - Thermal performance of MLI blankets. - Constant and variable conductance heat pipes, electro-osmotic heat pipe. - Radiation heat transfer. - Movable thermal joints and flexible thermal links. - Thermal analysis and design. - Two-phase heat transport systems: Their thermal- gravitational modelling and scaling, control methods/ algorithms. Two-phase test rigs development, components testing and calibration. - Thermal modelling of the ESA ATLID two-phase laser head thermal control system breadboard, and the ESA capillary pumped loop engineering model. - Development of the ESA high-efficiency low pressure drop two-phase condenser. - Adapting liquid flow metering assemblies for use in space. - Development of accurate ultrasonic flow meter for propellants. - TPX I: In-orbit two-phase experiment and TPX II, a re-flight of the modified two-phase experiment (parallel thermally unbalanced condensers configuration, high pumping power sintered nickel evaporators, upgraded controllable valve). - Loop heat pipe flight experiment. - Flexible external insulation blanket permeability. - Self regulating heaters. - ESA Thermal Analyzer & Fluid Heat Transfer Solver Upgrade. - Thermal modelling of laser heads, glove-boxes, the phased-array universal synthetic aperture radar structure, European co-operation for long-term in defence programme synthetic aperture radar antennae, avionics racks and components. - Meteosat Second Generation propellant gauging. Experimental determination of the dielectric properties of propellants. - Future European Space Transportation Investigations Program. S?nger aerospace plane thermal design activities. - Critical and novel issues, AMS-2 and CIMEX-3. - Pulsating two-phase loops and other pulsating/ oscillating heat transfer devices. - Small dedicated satellites: Wetsat & Sloshsat-Flevo. - Instrumentation for microgravity research. [Taken from abstract]. The full text is available as a PDF file.

Application of Direct and Large Eddy Simulation to Transition and Turbulence

This is Research and Technology Organization (RTO) AGARD-CP-551 , dated December 1994. The papers prepared for the AGARD Fluid Dynamics Panel (FDP) Symposium on 'Application of Direct and Large Eddy Simulation to Transition and Turbulence', which was held April 1994 in Greece are contained in this report. In addition, a Technical Evaluator's Report assessing the success of the Symposium objectives, and an edited transcript of the General Discussion are also included. In the past two decades significant progress has been made in the numerical simulation of turbulent flows. Vast improvements in speed and memory size of modern supercomputers, and recent progress in simulation algorithms and parallel computation have put us on the threshold of being able to simulate flows in configurations of engineering interest. For individual titles, see N95-21062 through N95-21098. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (114.43MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

ASME Digital Library

This service allows you to search ASME (American Society of Mechanical Engineers) journal articles back to 1985 and conference proceedings back to 2002. Search results provide bibliographic information and an abstract, with the option to purchase the full text, if you are not a subscriber.

Assessment of lift augmentation devices

This is Research and Technology Organization (RTO) AGARD-LS-43, dated February 1971. This publication contains edited versions of the lecture notes and complementary discussions from the AGARD - VKI Lecture Series on “Assessment of Lift Augmentation Devices”, at the von Karman Institute for Fluid Dynamics during the week 20-24 April 1970. The lecture series was designed to provide an up-to-date account of special aerodynamic problems and applications of lift-augmentation devices; including appraisals of the present state of knowledge, novel aerodynamic advances, experimental and theoretical treatments, applications for transport and combat aircraft, important areas for research and development. It was primarily intended for aeronautical engineers with a need to acquire a more adequate background on lift-augmentation devices. But short discussions were held after most of the lectures, together with a final Discussion Seminar, to take advantage of participants with specialised knowledge’ as appropriate. The Course was well supported as regards both the number of attendees (about 100) and their technical quality. The organisation was carried out under the auspices and with the support of AGARD, in collaboration with the von Karman Institute who had the responsibility for the general administration and local organisation. A special tribute must be paid to the lecture staff, for the quality of their presentations, the valuable analysis contained in their lecture notes provided for distribution during the Course, and their cooperative participation in discussions. Our thanks also go to the official and private organisations through whose courtesy it was possible to offer such technical experts as lecturers. Bibliographic and abstract details are available in HTML format. A table of contents and the full text (32.73MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

CFD Investigation of Effect of Depth to Diameter Ratio on Dimple Flow Dynamics

This is the full text of a thesis written by Robert Etter, which was presented to the Air Force Institute of Technology, Wright Patterson Air Force Base, Ohio in June 2007. This study aimed to further the understanding of laminar flow through a dimple with the goal of mitigating flow separation. Dimples of various depth to diameter ratios (0.05, 0.15) were examined for three different dimple diameters and chordwise locations, corresponding to diameter based (ReD) and chordwise location based (Rex) Reynolds number combinations of ReD 20500\Rex 5000, ReD 20500 Rex 77000, and ReD 9000 Rex 21000. For the last combination, a dimple of depth to diameter ratio of 0.25 was also examined. The dimples were placed in a flat plate located in a diverging channel causing an adverse pressure gradient encouraging flow separation near the dimple location. The flow was modeled in the commercial CFD solver Fluent. Results indicate that dimple depth to diameter ratio has a significant effect on the structure of dimple flow. The shallowest dimples showed little change to the overall flow in the channel. Deeper dimples contained dynamic vortical flow structures with behavior varying between each dimple studied. This dynamic vortex activity was observed to be linked with variances in downstream flow. The 0.15 depth to diameter ratio dimples showed behavior very similar to 0.10 ratio dimples investigated elsewhere. The 0.25 dimple show flow different in nature than 0.15 dimples for the same ReD and Rex; the differences were not as stark as those between 0.05 and 0.15 dimples. In light of this and other studies, dimple flow behavior is found to depend on a combination of parameters that eludes direct quantitative parameterization. However, the conclusion is drawn that the most effective dimple will be just deep enough to develop dynamic vortical activity and vortex shedding. [Taken from abstract]. This is in PDF format so Adobe Acrobat software is required in order to read it.

Concepts NREC

The company is a turbomachinery design and development organization providing all the resources required to develop complete solutions from concept through detailed engineering, product design, prototype production, performance testing and product manufacturing. The products developed by Concepts NREC cover the entire range of turbomachinery applications and markets including aerospace, military and commercial aviation, ground support, power generation, petrochemical and process equipment, refrigeration, biomedical, automotive, marine, and agriculture. The site contains descriptions of the company's products and services, and provides details of job opportunities, news and events. Copies of the Company's newsletter, SpinOffs, can be accessed online. Concepts NREC is also involved in education and training and a section of the site describes the company's courses and publications, including a number of turbomachinery handbooks and textbooks. An online bookstore is available for ordering purposes. The site also provides access to the full text of a select collection of Concepts NREC technical papers in PDF format, covering topics such as optimization, and the design of axial flow and centrifugal compressors and turbines.

Department of Aeronautics and Astronautics at the University of Southampton

The Department of Aeronautics and Astronautics at the University of Southampton is a member of the School of Engineering Sciences. The department name reflects the international reputation of Southampton in both Aeronautics & Astronautics and encompasses a broad range of disciplines within the field of aerospace engineering with applications to the specification, design and construction of airframes, engines, satellites and other spacecraft. These disciplines include aerodynamics, flight mechanics, materials, propulsion, structures, as well as aircraft and spacecraft systems. Cutting-edge research into all these disciplines is carried out within the School of Engineering Sciences by recognised experts in their specific fields. The web site gives information about the department, staff, research interests, the undergraduate and postgraduate courses available, facilities, including a wind tunnel complex which ranges from low speed to hypersonic, as well as the Department's links with industry and government research laboratories.

Department of Aeronautics at the Imperial College of Science, Technology and Medicine

The Web Site provides information on all major activities which are carried out by the Department, including teaching programmes, research and Departmental facilities, as well as the Departmental Staff. It contains information about the eight research groups - the Biomedical Flows Group, the Bluff Bodies and Vortex Flow Group, the Hypersonics Research Group, the Turbulence Mixing and Flow Control Group, the Spectral/hp Element Methods Group, the Geophysical Fluid Dynamics Group, the Turbulent Flow Modelling Group and the Flow Control Group. There are also links through to information about the Centre for Composite Materials within the department and the Honda Wind Tunnel. Details of undergraduate and postgraduate courses, short courses and research seminars are also provided.

Department of Aerospace Engineering at the University of Bristol

Part of the Faculty of Engineering, the Department of Aerospace Engineering at the University of Bristol has research interests in the areas of fluid flow and aerodynamics, thermo-fluid dynamics, dynamics and control systems, structures and materials, and space engineering. The site contains a description of the research activities of the department and information about staff, as well as available courses. The site also provide access to an article written by Sir Robert Wall which looks back over the University�s contribution to the first 100 years of manned flight.

Flexible Twist for Pitch Control in a High Altitude Long Endurance Aircraft with Nonlinear Response

This is the full text of a thesis written by Vanessa Bond which was presented to the Air Force Institute of Technology, Wright Patterson Air Force Base, Ohio, in December 2008. Information dominance is the key motivator for employing high-altitude long-endurance (HALE) aircraft to provide continuous coverage in the theaters of operation A joined-wing configuration of such a craft gives the advantage of a platform for higher resolution sensors. Design challenges emerge with structural flexibility that arise from a long-endurance aircraft design. The goal was to demonstrate that scaling the nonlinear response of a full-scale finite element model of a high-altitude long-endurance (HALE) aircraft was possible if the model was aeroelastically and nonlinearly scaled. A straight-forward method of scaling the first three natural vibration frequencies and mode shapes, and the first buckling eigenvalue was attempted. In addition to analytical scaling several experiments were accomplished to understand and overcome design challenges of HALE aircraft. One such challenge is combated by eliminating pitch control surfaces and replacing them with an aft-wing twist concept. This design was physically realized through wind tunnel measurement of forces, moments and pressures on a subscale experimental model proving that pitch control with aft-wing twist is feasible. Another challenge is predicting the nonlinear response of long-endurance aircraft. This was addressed by experimental validation of modeling nonlinear response on a subscale experimental model. The validation accomplished during this experiment on a subscale model will reduce technical risk for full-scale development of such pioneering craft. Nonlinearities can be attributed to follower forces, which were found to be a significant influence in HALE aircraft. [Taken from Abstract]. This is in PDF format so Adobe Acrobat software is required in order to read it.

Heat Transfer and Cooling in Gas Turbines

This is Research and Technology Organization (RTO) AGARD-CP-527, dated February 1993. The symposium was arranged in the following sessions: turbine blades--external heat transfer; turbine blades--internal heat transfer; measurement techniques; rotating disks, labyrinth seals, and shafts; combustors; design, interactions; and prediction methods. Heat transfer and cooling in gas turbines are still key factors for achieving high performance, increased life, and improved reliability. Any progress in this field will lead to a reduction of maintenance cost and fuel consumption. The purpose of the symposium was to bring together experts from industry, research establishments, and universities to discuss fundamental and applied heat transfer problems relevant to gas turbines, to exchange practical experience gained, and to review the state of the art. For individual titles, see N93-29927 through N93-29964. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (156.97MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Influence of Structural Flexibility on Flapping Wing Propulsion

This is the full text of a thesis written by Aaron McClung which was presented to the Air Force Institute of Technology, Wright Patterson Air Force Base, Ohio, in June 2009. The influence of structural deformations on the aerodynamic response of a flapping wing configuration was examined using Navier-Stokes based simulation. Two deformation modes, torsion and bending, were considered for an elastic axis along the leading edge of the wing. Both deformation modes influence the velocity and acceleration profile of the wing surface, altering the unsteady aerodynamic phenomena produced by the dynamic wing motion. The spanwise feathering rotation, or torsional response, alters the motion of the wing near the wing root. This variation in the acceleration profile influences the non-circulatory aerodynamic response and the local wake structures produced near the wing root during pronation and supination. Increased lifting forces and enhanced aerodynamic efficiencies were observed for a moderate increase in torsional exibility. Peak bending deformations near the wing tip also occur during pronation and supination, altering the velocity and acceleration profiles of the wing as the circulatory aerodynamic phenomena undergo a transition as the wing changes direction of motion. Because of the timing of the bending deformations, small tip deformations may have a significant influence on overall aerodynamic performance. [Taken from Abstract]. This is in PDF format so Adobe Acrobat software is required in order to read it.

Institute of Aerodynamics and Flow Technology

The Institute is a leading research institute in the field of aerodynamics/aeroacoustics of airplanes and aerothermodynamics of space vehicles. Part of the role of the Institute is to coordinate its research effort with the German / European Aerospace industry and with a large number of universities. It provides a link between the basic research conducted at the universities and the industrial application of the outcomes from that research. It has two main sites at Braunschweig and G?ngen and has a division at Cologne. The web site provides access to news information, and describes the Institute's Departmental stucture, its research interests, ongoing research projects, software products and publications.

Institute of Fluid Science, Tohoku University

The Institute conducts research on flow science in areas such as development of low-intrusive medical treatments with shock waves, creation of advanced technology for better utilization of natural energy sources, development of manufacturing processes of new materials, development of high-functionality material / fluid systems, and advancement of high-efficiency supersonic flight and space propulsion technology. The site describes in detail the research that it undertakes and also provides the Fluid Science Database, a searchable and browseable database of full text papers from the Institute.

Least-Squares Finite Element Formulation for Fluid-Structure Interaction

This is the full text of a thesis written by Cody Rasmussen which was presented to the Air Force Institute of Technology, Wright Patterson Air Force Base, Ohio, in March 2009. Fluid-structure interaction problems prove difficult due to the coupling between fluid and solid behavior. Typically, different theoretical formulations and numerical methods are used to solve fluid and structural problems separately. The least-squares finite element method is capable of accurately solving both fluid and structural problems. This capability allows for a simultaneously coupled fluid structure interaction formulation using a single variational approach to solve complex and nonlinear aeroelasticity problems. The least-squares finite element method was compared to commonly used methods for both structures and fluids individually. The fluid analysis was compared to finite differencing methods and the structural analysis type compared to traditional Weak Galerkin finite element methods. The simultaneous solution method was then applied to aeroelasticity problems with a known solution. Achieving these results required unique iterative methods to balance each domain's or differential equation's weighting factor within the simultaneous solution scheme. The scheme required more computational time but it did provide the first hands-off method capable of solving complex fluid-structure interaction problems using a simultaneous least-squares formulation. A sequential scheme was also examined for coupled problems.

Macroscopic Computational Model of Dielectric Barrier Discharge Plasma Actuators

This is the full text of a Master's thesis by Captain Timothy R. Klein, USAF, AFIT/GAP/ENP/06-07, which was presented to the Faculty Department of Engineering Physics of Air University's Air Force Institute of Technology, in February 2006. Recent progress in the generation and sustainment of gas discharges at atmospheric pressure has energized research in the field of plasma-aerodynamics. Plasma actuators are promising devices that achieve flow control with no moving parts, do not alter the airfoil shape and place no parts in the flow. The operation of a plasma actuator is examined using a macroscopic (force and power addition) computational fluid dynamic model of a dielectric barrier discharge, DBD, in Fluent. A parametric approach is adopted to survey the range of requisite magnitudes of momentum and energy delivered to the flow field and to identify the effects of this localized momentum and energy addition on the flow characteristics. Simulations consider the initiation and control of flow over a flat plate in a low velocity fluid. The simulation velocity profiles are compared with the experimental observations of Corke (AIAA 2002-0350) as well as simulations of Font (AIAA 2004-3574), Boeuf and Pitchford (JAP 97 103307 2005), and Roy and Gaitonde (AIAA 2005-4631). The simulation is extended from a flat plate simulation to examine the flow modification over an airfoil. Flow characteristics of lift and drag are compared with experimental results of Post and Corke (AIAA 2003-1024) and the compatible energy/momentum addition is identified. Energy and momentum values are then compared and related to characteristic values arising in DBD operation. [Taken from abstract]. The full text is available in PDF format on the Scientific and Technical Information Network (STINET) which is provided by the Defense Technical Information Center (DTIC).

Missile Aerodynamics

This is Research and Technology Organization (RTO) AGARD-R-804 dated June 1994. Lecture notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Missile Aerodynamics' have been assembled in this report. The aim and scope of this course was to present the current state of the art on specific topics of tactical missile aerodynamics. Specifically, topics and methods covered include: Aeromechanical Design of Modern Missiles, Semi-empirical Predictive Tools, Lateral Jet Control, High Angle of Attack Aerodynamics, Analysis and Modelling of Missile Infrared Radiation, Navier-Stokes Computations for Complete Missile Configurations, and Navier-Stokes and Euler Computations for Supersonic Air Intakes. The material assembled in this report was prepared under the combined sponsorship of the AGARD Fluid Dynamics Panel, the Consultant and Exchange Program of AGARD, and the von Karman Institute (VKI) for Fluid Dynamics. For individual titles, see N95-14446 through N95-14452. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (47.50MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Modeling, Simulation and Estimation of Optical Turbulence

This is the full text of a thesis written by Byron P. Formwalt which was presented to the Air Force Institute of Technology, Wright Patterson Air Force Base, Ohio in December 2006. The dissertation documents three new contributions to simulation and modeling of optical turbulence. The first contribution is the formulization, optimization and validation of a modeling technique called successively conditioned rendering (SCR). The SCR technique us empirically validated by comparing the statistical error of randon phase screens generated with the technique. The second crontribution is the derivation of the covariance delineation theorum, which provides theoretical bounds on the error associated with SCR. It is shown empirically that the theoreticalbound may be used to predict relative algorithm performance. Therefore the covariance delineation theorum is a powerful tool for optimising SCR algorithms. For the third contribution, we introduce a new method for passively estimating optical turbulence parameters and demonstrate the method using experimental data.

Nielsen Engineering & Research (NEAR)

NEAR provides consulting services and specialized software for aerodynamic analysis and design, especially launch vehicle aerodynamics, missile aerodynamics, and store separation. The web site provides a brief company overview. The company's research and development areas are described. These include: CFD, computational modeling, and fluid mechanics; aerodynamic prediction and design; flow control devices, microelectromechanical systems (MEMS), sensors; information technologies and intelligent systems; and mathematical modeling. These descriptions contain links to some full text papers produced by NEAR personnel. Other sections of the site cover consulting services and expertise, software products, hardware products, and publications for sale.

Numerical Investigation of Cavity-Vane Interactions within the Ultra Combat Combustor

This is the full text of a Master's thesis by Second Lieutenant Jonathan Anisko, USAF, AFIT/GAE/ENY/06-M01, which was presented to the Faculty Department of Aeronautics and Astronautics of Air University's Air Force Institute of Technology (AFIT), in March 2006. A numerical analysis and design optimization of the Ultra Compact Combustor (UCC) has been conducted. The UCC is a combustor designed to incorporate high-g loadings to increase flame propagation speed while reducing flame length, thereby helping to significantly reduce the size of a combustor. Since real experimental tests are expensive and construction time is prohibitive to test many different design configurations, CFD modeling of the UCC is used to speed up the design optimization process while reducing the overall costs. The CFD models have been validated by comparison to data from recent experimental tests. The use of periodic sections and grid independence were validated as well. Modifications to the physical configuration were then modeled using CFD. The shortening of the cavity was found to reduce the harmful emissions in the exhaust. Increasing the angle to 45 deg. and 55 deg. of the air inlets further improved the emissions by increasing the residence time of the fuel particles in the cavity. Aerodynamically improving the vane reduced the pressure loss of the combustor by up to 25%. The increased vane height was an initial step in scaling up the UCC to operational configurations. Of the models in this research, the most improved configuration was found to be the 45 deg. air inlet on the shortest cavity. [Taken from abstract]. The full text is available in PDF format on the Scientific and Technical Information Network (STINET) which is provided by the Defense Technical Information Center (DTIC).

Proceedings of the Institution of Mechanical Engineers, Part G : Journal of Aerospace Engineering

Published six times a year, the Journal of Aerospace Engineering is a forum for the communication of ideas and methods presently in use at the forefront of technology in the field of aerospace engineering. It contains papers on both theoretical and practical aspects of all types of civil and military aircraft and spacecraft and their support systems. The scope is wide, covering research, design, development, production, operation, servicing and repair, components and auxiliary equipment, safety and reliability. The site provides contents information for the journal. If you wish to view full text check with your library to see if they have a subscription.

Report of the high Reynolds number wind tunnel study group of the Fluid Dynamics Panel

This is Research and Technology Organization (RTO) AGARD-AR-35, dated April 1971. Modern aeronautical and aerospace systems are so expensive that every reasonable effort to minimize the risk in their development is warranted. If a weapon system like the F-I11 or an airplane like the Concorde suffers delays or outright failure as a result of unforeseen technological problems, the penalties to the companies and nations involved are staggering. The tried and proven way to minimize such risks on aerodynamic systems is to conduct extensive tests in adequate wind tunnel facilities. Higher costs of the future, large sophisticated aeronautical and aerospace systems make such testing even more imperative than is indicated by history. Wind tunnels of the NATO countries have been shown, during recent years, to be quite inadequate for tests for the large aeronautical systems under development. The intricacies and inaccuracies associated with extrapolation of wind tunnel data taken at a Reynolds number of 3 to 7 million for design of airfoils that operate at Reynolds numbers of over 150 million were thoroughly discussed at the von Krirmrin Institute’s lecture series on “Large Airplane Aerodynamics” . The study reported herein is adequate for the purposes of defining the performance and operating characteristics required in new, high Reynolds number wind tunnels, and conceptual tunnel designs which meet these requirements are proposed. Although the attention of the HIRT group was devoted almost exclusively to the transonic flight regime, the proposed tunnels could be designed to meet the high Reynolds number testing requirements throughout the transonic speed range. The wind tunnels recommended in this report can be built using existing technology. However, utility of the tunnels and the quality of the data that they will yield will be enhanced by vigorous support of a relevant research program. Bibliographic and abstract details are available in HTML format. A table of contents and the full text (8.01MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Sadhana : Academy Proceedings in Engineering Sciences

SADHANA is a bi-monthly research journal in English published by the Indian Academy of Sciences. The journal covers all branches of Engineering Science including mechanics (fluid, solid, thermal), computer science, electronics, energy, aerospace technology, materials science, nuclear engineering, systems analysis and alternative technologies. The full-text articles are available in PDF format.

Scale Effects on Aircraft and Weapon Aerodynamics

This is Research and Technology Organization (RTO) AGARD-AG-323, dated July 1994. The present state of knowledge on scale effects at high lift and low speeds, at transonic speeds, and on aircraft drag are presented. In addition, scale effects in various important specific scale-sensitive areas such as forebody vortex flows, the flow in and near open cavities, the flow into an air intake, the flow over propellers, and on ice accretion simulation testing are discussed. The emphasis is on scale effects that have been observed in flight-tunnel comparisons for specific aircraft. It is concluded that much has been learned about scale effects; however, precise prediction can still be difficult. Twenty recommendations for further research are mentioned. This AGARDograph has been produced at the request of the Fluid Dynamics Panel of AGARD. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (24.07MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Special Course on Aerothermodynamics of Hypersonic Vehicles

This is Research and Technology Organization (RTO) AGARD-R-761 , dated June 1989. This AGARD Fluid Dynamics Panel/von Karman Institute Special Course was inspired by new ventures in the hypersonic domain moving forward on both sides of the Atlantic-HERMES in Europe and the NASP (X-30) in the United States. Following the review of basic principles including real gas effects, a series of lectures were presented on experimental and computational methods specific to hypersonic flows. Stress was placed on measurement techniques developed primarily for flows with heat transfer, chemical reactions, strong shocks, and compressible boundary layers. Both surface measurements and flow field measurements including species concentration techniques, were discussed. The same spirit governed the lecture on computational methods: stress was placed on the new problems in CFD posed by high speeds and chemical reactions. The course finished with state of the art reviews on three critical flow problems: transition to turbulence; ininteractions between shocks and boundary layers; and shock/shock impingement. For individual titles, see N89-29307 through N89-29315. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (65.42MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Special Course on Progress in Transition Modelling

This is Research and Technology Organization (RTO) AGARD-R-793 , dated April 1994. Lecture notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Progress in Transition Modelling' have been assembled in this Report. The aim and scope of this Course was to provide information on new developments in modelling the dynamics of transition to turbulence, and the prediction of transition in boundary-layer flows. Specifically, topics and methods covered include: a physical description of boundary-layer transition, linear theory, asymptotic techniques, parabolized stability equations, direct numerical simulations, empirical methods and closure of the Reynolds' averaged Navier-Stokes equations. The material assembled in this report was prepared and presented under the combined sponsorship of the AGARD Fluid Dynamics Panel, and the von Karman Institute (VKI) for Fluid Dynamics. For individual titles, see N94-33885 through N94-33890. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (43.13MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Special course on Shock Wave/Boundary Layer Interactions in Supersonic and Hypersonic Flows

This is Research and Technology Organization (RTO) AGARD-R-792 , dated August 1993. Notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Shock-Wave/Boundary-Layer Interactions in Supersonic and Hypersonic Flows' are presented. The objective was to report on results from recent research programs providing a consolidated review of these activities and a sound basis for developing more reliable methodologies for future vehicle design. The course also provided a focused review of recent progress for swept interactions in both laminar and turbulent flows, including discussions: flowfield structure; scaling and similarity laws; effect of shock strength on flow feature; effect of shock generator geometry for a given shock strength; techniques for investigating swept interactions, particularly optical techniques; and contributions of numerical simulations to the understanding of swept interactions. The effects of turbulence and turbulence modeling on the flowfields are provided. For individual titles, see N94-15197 through N94-15203. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (48.50MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Special Course on Unstructured Grid Methods for Advection Dominated Flows

This is Research and Technology Organization (RTO) AGARD-R-787 , dated May 1992. Lecture notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Unstructured Grid Methods for Advection Dominated Flow' have been assembled in this report. The objective of this course was to provide state of the art information, as well as recent developments in unstructured grid methods, suitable for the computation of high Reynolds number compressible and incompressible flows, and other related subjects. A wide range of applications is presented, which includes incompressible free surface problems, transonic aerodynamics, and hypersonic reentry flows. For individual titles, see N92-27672 through N92-27680. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (56.05MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Steady and Transient Performance Prediction of Gas Turbine Engines

This is Research and Technology Organization (RTO) AGARD-LS-183, dated May 1992. Aero-thermodynamic performance prediction methods for gas turbine engines with respect to steady and transient operation are discussed. This includes advanced cycle calculation methods, also taking into account variable cycle engine types. A very important objective is the consideration of installation effects, i.e., Reynolds number and inlet distortions, as well as advanced control concepts for increasing engine surge margins. In addition to these topics, individual papers include practical considerations in designing the engine cycle, dynamic simulation, inlet distortion effects in aircraft propulsion system integration, 'smart' engines, and performance and health monitoring models. For individual titles, see N92-28459 through N92-28467. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (8.30MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Supersonic Aircraft Optimization for Minimizing Drag and Sonic Boom

This is a dissertation for the degree of doctor of philoshophy written by Martin K. Chan submitted to the department of Aeronautics and Astrophysics of Stanford University in 2003. This thesis describe a design tool incorporating classical sonic boom theory, computational fluid dynamics and a multi-objective genetic algorithm. This tool was developed for low-boom supersonic aircraft optimization. Both sonic boom and drag were optimized simultaneously and a Pareto optimal set of designs ranging from minimum boom to minimum drag was obtained for each optimization. Since sonic boom was optimized directly, the method had broader applicability than the traditional inverse method. A high-order three-dimensional panel method was used for sonic boom prediction. The traditional linear source model was fast but did not account for wing-body aerodynamic interaction. Euler solutions were expensive for computing sonic booms because a large number of grid points were needed to accurately predict the pressure signature away from the aircraft. For the Mach number and configurations of interest, the panel code showed good agreement with Euler but at a fraction of the cost. A loudness metric was shown to have advantages over initial overpressure and peak overpressure for measuring shaped sonic booms. However, optimization results obtained using calculated loudness raised concerns about the robustness of the solution to atmospheric disturbance. Peak overpressure minimization also produced reasonable sonic boom signatures and appeared more robust to atmospheric uncertainties, but the resulting loudness was not as good. Better convergence was also observed with peak overpressure. Two supersonic business jets were optimized. One was a conventional configuration; the other was a natural laminar flow configuration. Optimization results obtained using loudness and peak overpressure were compared. A non-axisymmetric fuselage was optimized and found to reduce the inviscid drag by 9 to 30 percent at the same sonic boom loudness. This PhD thesis is available free in PDF format (17Mb).

The aerodynamics of parachutes

This is Research and Technology Organization (RTO) AGARD-AG-295, dated July 1987. This AGARD report discusses the principal aerodynamic characteristics of parachutes and the factors which affect them. It is anticipated that its main readers will be recent engineering graduates entering research establishments, parachute companies or related industries so some appreciation of basic mechanics, the principles of computing and elementary fluid dynamics on the part of the reader has been assumed. Its contents include Steady-State and Unsteady Aerodynamics, Parachute Deployment and Inflation, Experimental Investigations, Methods of analysis, Extraterrestrial Parachute Applications, and some suggestions for future research. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (14.42MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Theoretical and Experimental Methods in Hypersonic Flows

This is Research and Technology Organization (RTO) AGARD-CP-514, dated April 1993. Papers prepared for the AGARD Fluid Dynamics Panel Symposium on theoretical and experimental methods in hypersonic flows held on 4-8 May 1992 are presented. The objectives of the Symposium were to (1) report and assess the advances being made by the AGARD community on the development and application of theoretical methods and experimental techniques for simulating hypersonic flows over aerospace vehicles; (2) highlight outstanding problem areas; and (3) establish pointers to aid in the planning and implementation of future research programs. Major topics covered by the Symposium were testing techniques and instrumentation, computational methods and physical modeling, and validation and accuracy assessment. For individual titles, see N94-10422 through N94-10465. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (117.34MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Turbomachinery Design Using CFD

This is Research and Technology Organization (RTO) AGARD-LS-195, dated May 1994. Computational Fluid Dynamics (CFD) has become a major design tool for designers of turbomachinery. The progress in this area is fast, and the use of 3-D methods is becoming increasingly applicable to the design process. This Lecture Series will include: (1) Computational methods for preliminary design and geometry definitions; (2) Methods for computing through-flows, blade-to-blade flows and geometry generation; (3) Optimization strategies; (4) Designing in three dimensions; (5) Code validation, mesh influence on solution accuracy; (6) Turbulence and transition modelling; (7) Comparison of time averaged flow solvers and 3-D unsteady CFD codes; (8) Industrial use of CFD and the points of view of the designers. For individual titles, see N95-14128 through N95-14136. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (66.39MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

Tutorial on Quantification of Differences Between Single - and Two-Component Two-Phase Flow and Heat Transfer

This technical report (NLR-TP-2003-037) was published by NLR (the National Aerospace Laboratory of the Netherlands) in 2003 and was written by A. A. M. Delil. Single-component two-phase systems are envisaged for aerospace thermal control applications: Mechanically Pumped Loops, Vapour Pressure Driven Loops, Capillary Pumped Loops and Loop Heat Pipes. Thermal control applications are foreseen in different gravity environments: Micro-g, reduced-g for Mars or Moon bases, 1-g during terrestrial testing, and hyper-g in rotating spacecraft, during combat aircraft manoeuvres and in systems for outer planets. In the evaporator, adiabatic line and condenser sections of such single-component two-phase systems, the fluid is a mixture of the working liquid (for example ammonia, carbon dioxide, ethanol, or other refrigerants, etc.) and its saturated vapour. Results of two-phase two-component flow and heat transfer research (pertaining to liquid-gas mixtures, e.g. water/air, or argon or helium) are often applied to support research on flow and heat transfer in two-phase single-component systems. The first part of the tutorial updates the contents of two earlier tutorials, discussing various aerospace-related two-phase flow and heat transfer research. It deals with the different pressure gradient constituents of the total pressure gradient, with flow regime mapping (including evaporating and condensing flow trajectories in the flow pattern maps), with adiabatic flow and flashing, and with thermal-gravitational scaling issues. The remaining part of the tutorial qualitatively and quantitatively determines the differences between single- and two-component systems: Two systems that physically look similar and close, but in essence are fully anything but negligible, in many cases. These differences (quantified by some examples) illustrates how careful one shall be in interpreting data resulting from two-phase two-component simulations or experiments, for the development of single- different. It was already elucidated earlier that, though there is a certain degree of commonality, the differences will be component two-phase thermal control systems for various gravity environments. [Taken from abstracct]. The full text is available as a PDF file.

Tutorial on Single - and Two - Component Two - Phase Flow and Heat Transfer : Commonality and Difference

This technical report (NLR-TP-2001-538) was published by NLR (the National Aerospace Laboratory of the Netherlands) in 2001 and was written by A. A. M. Delil. It is assessed to what extent the results of two-phase two-component flow and heat transfer research can be usefully applied to support research on the flow and heat transfer in two-phase single-component systems. The latter single-component two-phase systems, envisaged for spacecraft thermal control applications, are Mechanically Pumped and Vapour Pressure Driven Loops, Capillary Pumped Loops, and Loop Heat Pipes. In these single-component systems the working fluid is a mixture of a liquid (for example ammonia, carbon dioxide, ethanol, or other refrigerants, etc.) and its saturated vapour. The two-component systems considered consist of liquid-gas mixtures, e.g. water-air. Various aspects are discussed qualitatively and quantitatively to determine commonality and difference between two physically looking similar and close, but essentially different systems. It is focused on the different pressure gradient constituents and total pressure gradients, on flow regime mapping (including evaporating and condensing flow trajectories in the flow pattern maps), on adiabatic flow and the impact of flashing, and on thermal-gravitational scaling issues. It is elucidated that, though there is a certain degree of commonality, the differences are appreciable. The conclusion is that one shall be very careful in interpreting two-component outcomes to develop single-component two-phase thermal control systems. [Taken from abstract]. The full text is available as a PDF file.

University of Southampton School of Engineering Sciences : Aerodynamics and Flight Mechanics

This group is engaged in leading-edge research in fundamental fluid dynamics, computational aeroacoustics, applied aerodynamics and flight dynamics. Specific areas of research are industrial aerodynamics, high speed flows, fluid mechanics, applied aerodynamics and aeroacoustics and rotorcraft design and aircraft operations. The site describes research projects and facilities, provides information on staff and students including publications, and links to e-Prints Soton for full text publications.

Wall Interference, Support Interference and Flow Field Measurements

This is Research and Technology Organization (RTO) AGARD-CP-535, dated July 1994. The 31 papers prepared for the AGARD Fluid Dynamics Panel (FDP) Symposium on 'Wall Interference, Support Interference, and Flow Field Measurements' are contained in this report. In addition, a Technical Evaluator's Report assessing the success of the Symposium in meeting its objectives, and an edited transcript of the General Discussion held at the end of the meeting are also included. The primary objective of this Symposium was to report on recent developments from research and technology programs aimed at reducing test data errors caused by wind tunnel walls, model supports, and intrusive flow field measurement devices. The scope of papers included wall interference correction methods based on measured data at the walls and methods to eliminate wall interference through adaptive and/or ventilated walls, support interference calculations and correction methods, and recent advances in flow field measurement techniques. For individual titles, see N95-19252 through N95-19282. Bibliographic and abstract details are available in HTML format. A table of contents, and the full text (128.87MB) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library.

World Academy of Science, Engineering and Technology (WASET)

World Academy of Science, Engineering and Technology organises and conducts conferences, workshops, symposia and publishes scientific journals. Notably the site provides details of forthcoming International Conference on Computer, Electrical, and Systems Science, and Engineering (CESSE) conferences that WASET is organising. Topics include fluid mechanics, heat transfer and thermodynamics, aerospace sciences and aviation technologies, computer science and engineering and modelling and simulation.

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