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COMPUTATIONAL ANALYSIS OF OFF-DESIGN WAVERIDERS

JOURNAL OF AIRCRAFT 1994年第2期31卷 345-353页

作者： HE, X RASMUSSEN, ML University of Oklahoma Norman Oklahoma 73019

Comprehensive inviscid and viscous numerical simulations of hypersonic flow past nonconical rounded-nose waveriders are presented. The flowfields and aerodynamic forces at off-design conditions are determined inviscidly by a space marching cfd code with the initial data plane provided by a time marching Navier-Stokes cfd code. Off-design conditions include off-design Mach numbers, angles of attack, and rounded leading edges. A wide range of waverider configurations is investigated and compared. On-design viscous flows past a waverider with a sharp leading edge at M(infinity) = 4 and at different Reynolds numbers and temperature boundary conditions are obtained by a time marching Navier-Stokes solver. These calculations show the effects of viscous interactions, which are influential near the leading edges, and determine the viscous drag. The inviscid calculations show that L/D decreases as M(infinity) increases (with alpha = 0). At the on-design Mach numbers, the maximum L/D may occur at slight positive or negative alpha, depending on the shape of the waverider, and zero lift occurs at a negative alpha approximately equal to half of the body thickness. The effects of slight leading-edge blunting produce only local effects in the flowfield and small losses in L/D. The characters of the flowfields in the base plane are illustrated.

关键词： Aerodynamic Properties Lift to Drag Ratio Waverider Angle of Attack Two Dimensional Flow euler cfd code Numerical Simulation Navier Stokes Solver Shock Layers Winglets

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Numerical simulations and planar laser-induced fluorescence imaging results of hypersonic reactive flows

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JOURNAL OF PROPULSION AND POWER 2000年第1期16卷 16-21页

作者： Toshimitsu, K Matsuo, A Kamel, MR Morris, CI Hanson, RK Kyushu Univ Dept Aeronaut & Astronaut Fukuoka 81281 Japan Keio Univ Dept Mech Engn Kohoku Ku Yokohama Kanagawa 223 Japan Stanford Univ High Temp Gasdynam Lab Dept Engn Mech Stanford CA 94305 USA

This paper shows comparisons between computational fluid dynamics (cfd) calculations and planar laser-induced fluorescence and schlieren measurements of inert and reactive hypersonic hows around two-dimensional and axisymmetric bodies. In particular, both hydrogen-oxygen and methane-oxygen chemical reactions are considered for the shack-induced combustion in hypersonic flows. The hydrogen-oxidation mechanism consists of an existing mechanism of 8 reacting species and 19 elementary reactions. The reduced model of the methane-oxidation mechanism is newly derived from the GRI-Mech 1.2 optimized detailed chemical reaction mechanism, and consists of 14 species and 19 chemical reaction steps. Both chemical reaction mechanisms are combined with a point-implicit euler cfd code. The OH species density distributions of the present numerical calculations and imaging experiments for both mixtures are found to be in qualitative agreement.

关键词： Planar Laser Induced Fluorescence Total Variation Diminishing euler cfd code Projectiles Bow Shock Mach Numbers Conservation Equations Chemical Kinetics Stagnation Point Combustion Mechanism

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Wing optimization using design of experiment, response surface, and data fusion methods

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JOURNAL OF AIRCRAFT 2003年第4期40卷 741-750页

作者： Keane, AJ Univ Southampton Southampton SO17 1BJ Hants England

An empirical drag prediction model plus design of experiment, response surface, and data-fusion methods are brought together with computational fluid dynamics (cfd) to provide a wing optimization system. This system allows high-quality designs to be found using a full three-dimensional cfd code without the expense of direct searches. The metamodels built are shown to be more accurate than the initial empirical model or than simple response surfaces based on the cfd data alone. Data fusion is achieved by building a response surface kriging of the differences between the two drag prediction tools, which are working at varying levels of fidelity. The kriging is then used with the empirical tool to predict the drags coming from the cfd code. This process is much quicker to use than direct searches of the cfd.

关键词： Design of Experiments Data Fusion euler cfd code Aspect Ratio Thickness to Chord Ratio Aerodynamic Design Computing Effort Parallel Computing Environment Angle of Attack Structural Modeling

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Parametric Influence on Rotating Detonation Combustion: Insights from Fast Reactive euler Simulations

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AIAA JOURNAL 2024年第1期62卷 127-139页

作者： Klopsch, Roman Garan, Niclas Bach, Eric Paschereit, Christian Oliver Bohon, Myles D. Tech Univ Berlin Chair Pressure Gain Combust D-10623 Berlin Germany Tech Univ Berlin Chair Combust Kinet D-10623 Berlin Germany Tech Univ Berlin Chair Fluid Dynam D-10623 Berlin Germany

A two-dimensional unsteady reactive euler solver is employed to model rotating detonation combustion (RDC). A baseline case is chosen, and several combustor geometric and design parameters are varied individually in order to assess their effect on flowfield structure, exhaust flow properties, and performance. The parameters of interest are the perimeter and axial lengths of the combustor annulus, mass flux, outlet throat area, air injector throat area, and equivalence ratio. Quantification of the isentropically available work (IAW) in the exhaust flow is employed as a performance criterion. IAW is primarily affected by mass flux and outlet throat area through the effects of one-dimensional flow and, to a lesser degree, by perimeter and axial length through changes in the fraction of the flow that experiences irreversible shock processing. For all cases in the present study, this fraction appears to be solely determined by the ratio of detonation height to axial length. This ratio is also highly correlated to the angle of the oblique shock and the strength of the flow fluctuations. The predicted wave speed is between 90 and 95% of the Chapman-Jouguet velocity for a range of equivalence ratios between 0.6 and 1.4.

关键词： Constant Volume Combustion Oblique Shock Wave Detonation Waves Rotating Detonation Combustor Rotating Detonation Engine Pressure Gain Combustion Computational Fluid Dynamics euler cfd code Reacting Flows and Combustion

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Aeroelastic Modeling and cfd Simulation of Wind-Tunnel Scale Aspect Ratio 13.5 Common Research Model

Aeroelastic Modeling and CFD Simulation of Wind-Tunnel Scale...

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AIAA Aviation Forum and Exposition

作者： Xiong, Juntao Nguyen, Nhan Stanford, Bret K. Bartels, Robert E. KBR Wyle Inc Intelligent Syst Div Moffett Field CA 94035 USA NASA Ames Res Ctr Intelligent Syst Div Moffett Field CA 94035 USA NASA Langley Res Ctr Aeroelast Branch Hampton VA 23681 USA NASA Langley Res Ctr MS 340 Hampton VA 23681 USA

ISBN: (数字)9781624106101

ISBN: (纸本)9781624106101

This paper presents an aeroelastic modeling and simulation study of an aspect ratio 13.5 wind-tunnel scale Common Research Model (CRM) with distributed flaps. A vortex-lattice VSPAERO model of the CRM model is developed. A transonic small disturbance/integral boundary layer correction method is implemented in the VSPAERO model to account for the transonic and viscous flow effects. The structural deformation of the CRM model is calculated using a NASTRAN equivalent beam model. The VSPAERO model is coupled to the NASTRAN equivalent beam model to provide a rapid aero-structural analysis. A validation of the VSPAERO aeroelastic model is conducted by comparing the results to FUN3D cfd aeroelastic simulation results. An aerodynamic database is generated using the developed VSPAERO aeroelastic model for the real-time drag optimization and maneuver load alleviation study of the wind-tunnel scale CRM model.

关键词： Aeroelastic Analysis Aspect Ratio Low Speed Wind Tunnel Vortex Lattice Method Structural Analysis Potential Flow euler cfd code Nastran Turbulent Boundary Layer Vortex Rings

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Flutter Analysis of the Transonic Truss-Braced Wing Aircraft Using Transonic Correction

Flutter Analysis of the Transonic Truss-Braced Wing Aircraft...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Nguyen, Nhan Fugate, Jason Xiong, Juntao Kaul, Upender NASA Ames Res Ctr Intelligent Syst Div Moffett Field CA 94035 USA Stinger Ghaffarian Technol Inc Intelligent Syst Div Moffett Field CA 94035 USA NASA Ames Res Ctr Computat Aerosci Branch NASA Adv Supercomp NAS Div Moffett Field CA 94035 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

This paper describes a flutter analysis method for the Transonic Truss-Braced Wing aircraft using a vortex-lattice method coupled to an unsteady transonic correction method to account for unsteady aerodynamics in transonic flow. A steady-state vortex-lattice model of the Truss-Braced Wing aircraft is developed using vortex-lattice code VSPAERO. A transonic and viscous flow correction method is implemented in the VSPAERO model to account for steady-state transonic and viscous flow effects using transonic small disturbance code TSFOIL coupled to an in-house integral boundary layer code. In addition, a wing-strut interference correction method is developed to account for the transonic interference aerodynamics in the strut juncture region using high-fidelity cfd code FUN3D. A structural dynamic finite-element model of the Truss-Braced Wing aircraft is developed using BEAM3D in-house finite-element code and is coupled to the VSPAERO. The BEAM3D model includes a geometric nonlinearity due to the tension in the strut which causes a deflection-dependent nonlinear stiffness. An unsteady transonic correction method is developed to better capture the unsteady aerodynamics in transonic flow. The unsteady transonic correction method makes use of the Theodorsen's theory to account for the amplitude and phase shift of the unsteady lift coefficient in transonic flow. A preliminary flutter analysis of the Truss-Braced Wing aircraft is conduct to illustrate the unsteady transonic correction approach.

关键词： Structural Damping Transport Aircraft Trusses Aerodynamic Performance Transonic Aerodynamics Unsteady Transonic Flow Structural Finite Elements euler cfd code Turbulent Boundary Layer Vortices

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Fuselage shape optimization of a wing-body configuration with nacelles

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JOURNAL OF AIRCRAFT 2003年第2期40卷 297-302页

作者： Makino, Y Iwamiya, T Lei, Z Natl Aerosp Lab Tokyo 1828522 Japan VINAS Co Ltd Osaka 5500002 Japan

An aerodynamic design tool that combines a computational fluid dynamics code with an optimization technique for a drag minimization is developed and applied to a fuselage shape optimization of a Mach 1.7 scaled supersonic experimental airplane. An airframe/nacelle integration is taken into consideration. The optimized fuselage is compared with a conventional axisymmetrical area-ruled fuselage designed by a linear theory. The results indicate that a nonaxisymmetrical fuselage design concept with this optimization design tool is effective for the reduction of pressure drag, especially in the design of an airplane that generates a strong interference drag between its airframe and nacelles.

关键词： Shape Optimization Airframes Aeroplane Aerodynamic Design Interference Drag Wing Body Configuration National Experimental Supersonic Transport National Aerospace Laboratories Sensitivity Analysis euler cfd code

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