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Interactional aerodynamics A Quantative Analysis of Viscous and Lift-Induced Drag Components from Detailed Wake Measurements Behind a Half-Span Model This technical report (NLR-TP-2002-320) was published by NLR (the National Aerospace Laboratory of the Netherlands) in 2002 and was written by F. L. A. Ganzevles, A. C. de Bruin and W. Puffert-Meissner. In the Low Speed wind Tunnel (LST) of DNW detailed wake surveys were made behind an aircraft half-span model (ALVAST) using a rake with 5-hole probes. Different model configurations were considered including a body with wing, a body with wing and a Through Flow Nacelle (TFN) and a body with wing and a low-powered CRUF (Counter Rotating Ultra-high-bypass Fan). The lift and drag coefficients calculated from the measured velocities and pressures in the wake are compared with the force coefficients measured with a force balance. The spanwise distributions of lift, viscous drag and induced drag are presented. [Taken from abstract]. The full text is available as a PDF file. 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. Computational Aerodynamic Analysis of the Flow Field About a Velocity Test Sled This is the full text of a thesis by Andrew J. Lofthouse which was presented to the Graduate School of Engineering and Management of Air University's Air Force Institute of Technology (AFIT), in March 2002. It is available in PDF format. Abstract: The flow field about the nose section of a hypervelocity test sled is computed using computational fluid dynamics. The numerical model of the test sled corresponds to the Nike O/U narrow gage sled used in the upgrade program at the High Speed Test Track facility, Holloman Air Force Base, New Mexico. The high temperatures and pressures resulting from the aerodynamic heating and loading affect the sled structure and the performance of the vehicle. The sled transitions from an air environment to a helium environment at a speed of approximately 3,300 feet per second (Mach 3 in air, Mach 1.02 in helium) to reduce the effects of high Mach number flows. Steady, three-dimensional, inviscid flow solutions are computed for Mach numbers of 2 and 3 in air (2,200 and 3,300 feet per second), and for Mach numbers of 1.02, 2.5 and 3.1 in helium (3,300, 8,076 and 10,000 feet per second). Mesh adaptation is used to obtain a mesh-independent solution. Second-order solutions are obtained for the Mach 3 in air and Mach 1.02 in helium cases. The unsteady transition from air to helium at 3,300 feet per second is also modeled. Mach 3 in air computations are compared with analytical results. Dynamic Aeroelastic Analysis of Wing/Store Configurations This is the full text of a Doctoral thesis by Major Gregory H. Parker, USAF, AFIT/DS/ENY/06-06, which was presented to the Faculty Graduate School of Engineering and Management of Air University's Air Force Institute of Technology (AFIT), in December 2005. Limit-cycle oscillation, or LCO, is an aeroelastic phenomenon characterized by limited amplitude, self-sustaining oscillations produced by fluid-structure interactions. In order to study this phenomenon, code was developed to interface a modal structural model with a commercial computational fluid dynamics program. LCO was simulated for a rectangular wing, referred to as the Goland+ wing. It was determined that the aerodynamic nonlinearity responsible for LCO in the Goland+ wing was the combination of strong trailing-edge and lambda shocks which periodically appear and disappear. This mechanism limited the flow of energy into the structure which quenched the growth of the flutter, resulting in a steady LCO. Under-wing and tip stores were added to the Goland+ wing to determine how stores affected limit-cycle oscillation. It was found that aerodynamic store shapes affect LCO in two off-setting ways: under-wing stores interfere with the airflow on the lower surface of the wing which decreases LCO amplitudes, whereas, aerodynamic forces on both under-wing and tip stores directly increase LCO amplitudes. [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). Flight Test Measurement Techniques for Laminar Flow This is Research and Technology Organization (RTO) AGARDograph, RTO-AG-300-V23, edited by D. Fisher, K.H. Horstmann and H. Riedel; sponsored by the Flight Test Technology Team (FT3) of the Systems Concepts and Integration Panel (SCI) of RTO, dated October 2003. This AGARDograph provides information on flight test techniques, instrumentation, environmental effects, and flight procedures that have been used successfully in laminar flow research. Many techniques are described for measuring the location of boundary layer transition in-flight, from the very simple to the more complex. References to previous works are included for readers to explore. Specific instrumentation for flight is described and the unique environmental effects of flight noted. Procedures for flight test maneuvers are also included. Techniques discussed cover both local and global measurements. Some of the local flow techniques include surface temperatures, hot-film and hot-wire anemometry, raised-pitot, and traversing surface pitot. Global flow techniques include the infrared imaging, oil flow, liquid crystal, sublimating chemicals, and emitted fluid techniques. Some of the environmental concerns discussed include atmospheric particulate (ice crystals) and turbulence. Flight test procedures for infrared imaging and for insect contamination avoidance are described. Bibliographic details and an abstract are available in HTML format. The full text can be accessed online in PDF format (103 Mb) from the RTO's web site. High Speed Body Motion in Water This is Research and Technology Organization (RTO) AGARD Report, AGARD-R-827, dated February, 1998. It was sponsored by the Advisory Group for Aerospace Research and Development. This report is a compilation of the edited proceedings of a Workshop on "High Speed Body Motion in Water" held at the National Academy of Sciences in Kiev, Ukraine, 1-3 September 1997. Technical topics covered during the workshop included Hydrobionics, Boundary Layer Flows, Supercavitating Flows, Air-water Penetration and Control of Cavitation. Bibliographic details and an abstract are available in HTML format and the full text is available in PDF format (80 Mb)from the RTO's web site. Internal Aerodynamics in Solid Rocket Propulsion This is a Research and Technology Organization (RTO) Educational Note, RTO-EN-023, Paris, January 2004. The material in this publication was assembled to support a RTO/VKI Special Course under the sponsorship of the Applied Vehicle Technology Panel (AVT)and the von Kármán Institute for Fluid Dynamics (VKI) presented on 27-31 May 2002 in Rhode-Saint-Genčse, Belgium. These RTO-AVT/VKI Special Course notes provide the state of the art in internal aerodynamics in solid rocket propulsion, in a way accessible to attendees coming from both academic and industrial areas. Two families of solid motors can be identified: tactical rockets and large boosters for launch vehicles. The military rockets are subjected to combustion instabilities while vortex shedding drives the instabilities in the large boosters. After an overview of the motor internal flow dynamics, combustion of solid propellants and metal particulates were presented. Numerical modeling of internal flow aerodynamic, two-phase flow and flow/structural interactions were addressed, before focusing on the motor flow and combustion instabilities. Bibliographic and abstract details are available in HTML format. A table of contents, individual papers and the full text of the document (18.6 Mbytes) can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library. Rotor / Fuselage Unsteady Interactional Aerodynamics : A New Computational Model This web page provides access to a Virginia Polytechnic Institute and State University Department of Aerospace and Ocean Engineering PhD dissertation, by David Douglas Boyd, Jr, dated 27 July 1999. The thesis describes the development of a new unsteady rotor/fuselage interactional aerodynamics model. Comparisons are made between predictions using this new model and experiments for an isolated rotor and for a coupled rotor/fuselage configuration. Bibliographic and abstract details are available in HTML format. The full text of the document is accessible online in PDF format [19.69 Mb]. This title is part of Virginia Tech’s Electronic Thesis and Dissertation Collection (VT ETD). Symposium on Advanced Flow Management This site provides access to a Research and Technology Organization Meeting Proceedings, RTO-MP-069 (I), Paris, March 2003. The document contains papers presented at the Symposium of the RTO Applied Vehicle Technology Panel (AVT) Specialists’ Meeting held in Loen, Norway, 7-11 May 2001. Part A contains forty eight papers from a symposium on Vortex Flows and High Angle of Attack for Military Vehicles. Part B of the report contains papers from a separate and distinct symposium on Heat Transfer and Cooling in Propulsion and Power Systems, which was held concurrently. A table of contents, and the full text (157 Mbytes) of the document can be accessed online in PDF format. The document is contained in the RTO's Full Text Publication Library. The Combined Effects of Freestream Turbulence, Pressure Gradients, and Surface Roughness on Turbine Aerodynamics The site provides access to an Air University, Air Force Institute of Technology, Graduate School of Engineering and Management, MSc Thesis, by Second Lieutenant Christine P. Ellering, USAF, AFIT/GAE/ENY/02-5, dated March 2002. This research uses scaled facsimiles of real turbine blade surfaces to characterize correlations between blade roughness, with the combined effects of freestream turbulence and pressure gradients, and skin friction coefficient. Citation and abstract details are provided in HTML format, and the full text is available for downloading as a PDF file. This is one of the collection student research studies available from Air University's Research Web. Time-Domain Simulations of Aerodynamic Forces on Three-Dimensional Configurations, Unstable Aeroelastic Responses, and Control by Neural Network Systems This is a Virginia Polytechnic Institute and State University Department of Engineering Science and Mechanics PhD dissertation, by Zhicun Wang, dated May 7, 2004. In this study the nonlinear interactions between aerodynamic forces and wing structures are numerically investigated as integrated dynamic systems, including structural models, aerodynamics, and control systems, in the time domain. An elastic beam model coupled with rigid-body rotation is developed for the wing structure, and the natural frequencies and mode shapes are found by the finite-element method. A general unsteady vortex-lattice method is used to provide aerodynamic forces. This method is verified by comparing the numerical solutions with the experimental results for several cases; and thereafter applied to several applications such as the inboard-wing/twin-fuselage configuration, and formation flights. Flutter analysis is carried out for a High-Altitude-Long-Endurance aircraft wing cantilevered from the wall of the wind tunnel, a full-span wing mounted on a free-to-roll sting at its mid-span without and with a center mass (fuselage). In addition, a predictive control technique based on neural networks is investigated to suppress flutter oscillations. Bibliographic and abstract details are available in HTML format. The full text of the document is accessible online in PDF format [5.11 Mb]. This title is part of Virginia Tech’s Electronic Thesis and Dissertation Collection (VT ETD) Turbulence in Compressible Flows This is Research and Technology Organization (RTO) AGARD Report, AGARD-R-819, dated June 1997. Lecture notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Turbulence in Compressible Flows' have been assembled in this report. The following topics were covered: Compressible Turbulent Boundary Layers, Compressible Turbulent Free Shear Layers, Turbulent Combustion, DNS/LES and RANS Simulations of Compressible Turbulent Flows, and Case Studies of Applications of Turbulence Models in Aerospace. Bibliographic details and an abstract are available in HTML format and the full text is available in PDF format (160 Mb)from the RTO's web site. Wake Modelling Accuracy Requirements for Prediction of Rotor Wake-Stator Interaction Noise AIAA Paper 2003-3138 This technical report (NLR-TP-2003-124) was published by NLR (the National Aerospace Laboratory of the Netherlands) in 2003 and was written by P. Sijtsma and J. B. H. M. Schulten. Rotor wake-stator interaction is an important element of aircraft engine noise, especially in the rear arc. For numerical predictions of this type of engine noise, an accurate rotor wake description is indispensable. However, for most CFD codes accurate calculation of the development of turbulent rotor wakes is not something natural. To assess the importance of wake modelling accuracy, the NLR lifting surface model was used for a parametric study. Many rotor wake-stator interaction calculations were made on a configuration with realistic dimensions. Systematic variations of wake depth, wake width, and axial and circumferential position of the wake origin were carried out. It was found that for 1 dB precision in the final acoustic result these parameters must have a relative accuracy varying from 6% to 12%. This is a real trial of strength for most CFD models. With the same 1 dB precision requirement, it was found that relative errors in the prediction of rotor viscous drag, which is an important factor in the wake development, are acceptable up to 23%. [Taken from abstract]. The full text is available as a PDF file. |
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