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Optimization of Flapping Motion Parameters for Two Airfoils in a Biplane Configuration

JOURNAL OF AIRCRAFT 2009年第2期46卷 583-592页

作者： Kaya, Mustafa Tuncer, Ismail H. Jones, Kevin D. Platzer, Max F. Middle E Tech Univ Dept Aerosp Engn TR-06531 Ankara Turkey USN Postgrad Sch Dept Mech & Astronaut Engn Monterey CA 93943 USA

Flapping motion parameters of airfoils in a biplane configuration are optimized for maximum thrust and/or propulsive efficiency. Unsteady, viscous flowfields over airfoils flapping in a combined plunge and pitch are computed with a parallel flow solver on moving and deforming overset grids. The amplitudes of the sinusoidal pitch and plunge motions and the phase shift between them are optimized for a range of flapping frequencies. A gradient-based optimization algorithm is implemented in a parallel computing environment. The deforming overset grids employed remove the restriction on the flapping motion of airfoils, and improve the optimization results obtained earlier. In the Strouhal number range 0.17 < Sr < 0.25, an airfoil in a biplane configuration produces more thrust than a single airfoil. Yet, at a higher Strouhal number, the airfoil in a biplane configuration produced less thrust at a significantly lower efficiency than a single flapping airfoil.

关键词： Biplane Flapping Airfoil Propulsive Efficiency Flapping Frequency Strouhal Number Separated Flows parallel computing environment Optimization Algorithm Aerodynamic Performance Freestream Mach Number

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parallel overset-grid Euler solution of generic wing pylon and finned store

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JOURNAL OF AIRCRAFT 2005年第5期42卷 1337-1339页

作者： Tarhan, E Kavsaoglu, MS Turkish Aircraft Ind Inc TUSAS Technol Dev Dept TR-06520 Ankara Turkey Istanbul Tech Univ Dept Aeronaut Engn TR-34469 Istanbul Turkey

SINCE the 1980s, after Steger et al. solved two- and three-dimensionalmultibody configurations, overset (chimera) grid systems became very popular because of theiradvantages in easing the grid generation. Later in 1994, Kao et al. used overset grids in order toperform grid adaptation in the flow regions where higher gradients exist. Tuncer preferred to useoverset grids for unsteady Navier-Stokes solutions of sinusoidally pitching airfoil. Cho et *** the generic wing/pylon/finned store (WPFS) configuration as a steady three-dimensionalproblem by using the overset grids. Later Lee et al. used overset grid system for the solution of astore release problem. Furthermore, Hoist also developed a new search algorithm for locating thedonor cells associated with the overset grid system used in the solution of wing-fuselage geometryby full potential equations. In the present work, a three-dimensional finite differencing scheme,multiblock structured Euler and thin-layer Navier-Stokes solver is modified in order to enhanceoverset grid capability and to run in a parallel-computing environment. A wing-store configurationand Eglin WPFS configuration are selected as the test cases for the validation purposes.

关键词： Message Passing Interface Pressure Coefficient Search Algorithm Angle of Attack parallel computing environment Navier Stokes Equations Freestream Mach Number Solution Algorithm Wind Tunnel Tests Pitching Airfoil

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parallel computing of an integral formulation of transient radiation transport

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JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER 2003年第4期17卷 425-433页

作者： Lu, X Hsu, PF Florida Inst Technol Dept Mech & Aerosp Engn Melbourne FL 32901 USA

parallel computing of the transient radiative transfer process in participating media is studied with an integral equation model. Two numerical quadratures are used: the discrete rectangular volume (DRV) method and YIX method. The parallel versions of both methods are developed for one-dimensional and three-dimensional geometries, respectively. Both quadratures achieve good speedup in parallel performance. Because the integral equation model uses very small amount of memory, the parallel computing can take advantage of having each processor store the full spatial domain information without using the typical domain decomposition parallelism, which will be necessary in other solution methods, for example, discrete ordinates and finite volume methods, for large-scale simulations. The parallel computation is conducted by assigning a different portion of the quadrature to different compute node. In DRV method a variation of the spatial domain decomposition is used. In the case of YIX scheme, the angular quadrature is divided up according to the number of compute nodes. These parallel schemes minimize the communications overhead. Two new discrete ordinate sets are used in the YIX angular quadrature, and their parallel performances are discussed. One of the discrete ordinates sets, called a spherical ring set, is also suitable for use in the conventional discrete ordinates method.

关键词： parallel computing environment Radiative Transfer Message Passing Interface Optical Thickness parallel Algorithm Open Source Software Numerical Modeling Kernel Functions Connection Machine Radiation Properties

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Particle swarm optimization

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AIAA JOURNAL 2003年第8期41卷 1583-1589页

作者： Venter, G Sobieszczanski-Sobieski, J Vanderplaats Res & Dev Inc Colorado Springs CO USA NASA Langley Res Ctr Analyt & Computat Methods Branch Hampton VA 23665 USA

How the search algorithm known as particle swarm optimization performs is demonstrated. Particle swarm optimization is applied to structural design problems, but the method has a much wider range of possible applications. Improvements are contributed to the particle swarm optimization algorithm and conclusions and recommendations as to the utility of the algorithm are made. Results of numerical experiments for both continuous and discrete applications are presented. The results indicate that the particle swarm optimization algorithm does locate the constrained minimum design in both continuous and discrete applications and problems with multiple local minima, with very good precision. Additionally, particle swarm optimization has the potential of efficient computation with very large numbers of concurrently operating processors.

关键词： Particle Swarm Optimization Structural Optimization Search Algorithm Cantilever Beam Number of Particles Genetic Algorithm parallel computing environment Allowable Stress Bending Moment Annealing Process

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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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Optimal three-dimensional nozzle shape design using CFD and parallel simulated annealing

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JOURNAL OF PROPULSION AND POWER 2002年第1期18卷 217-221页

作者： Wang, X Damodaran, M Nanyang Technol Univ Sch Mech & Prod Engn Ctr Adv Numer Engn Simulat Singapore 639798 Singapore

Design optimization of the 3D aerodynamic shape of high-speed internal flow systems using CFD methods for Euler and Navier-Stokes equations and parallel SA algorithms have been implemented on multiple processors. The computed results show that parallel simulated annealing (PSA) appears to be a robust and simple approach for the design of complex problems such as 3D aerodynamics on coarse-grained parallel computer and that the evaluations of objective function can be reduced to the same level as generic gradient-based methods. A reasonable number of processors can be used in the implementation of PSA for achieving satisfactory speed up and efficiency. In the current work a relatively coarse grid system is used for the case study considering simplicity and for feasibility demonstration purposes. The impact of viscous effects should be considered with finer grids and improved turbulence models in the context of high-resolution numerical schemes in practical applications. The impact of the choices of parametric surface definition of the nozzle geometrical shape on the evolution of optimized shape should also be considered in the context of this work. (Author)

关键词： Nozzle Walls Annealing Ion Thruster Magnetic Materials Total Variation Diminishing Navier Stokes Equations Sensitivity Analysis parallel computing environment Message Passing Interface Genetic Algorithm

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Random packs and their use in modeling heterogeneous solid propellant combustion

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JOURNAL OF PROPULSION AND POWER 2001年第4期17卷 883-891页

作者： Kochevets, S Buckmaster, J Jackson, TL Hegab, A Univ Illinois Dept Mech & Ind Engn Urbana IL 61801 USA Univ Illinois Dept Aeronaut & Astronaut Engn Urbana IL 61801 USA Univ Illinois Ctr Simulat Adv Rockets Urbana IL 61801 USA

It is shown that random packs of spheres of various sizes can be constructed that model ammonium-perchloratein-binder propellants in the sense that both the size distributions and the packing fractions of industrial propellant packs can be matched, Strategies for dealing with fractional numbers of large particles are addressed, as are strategies for dealing with a large number of very fine particles (fine powder), Fine powder is necessary in a three-dimensional pack to achieve the required stoichiometric ratio of ammonium perchlorate to fuel binder, but is not necessary in a two-dimensional (disk) pack, Some preliminary calculations of the two-dimensional combustion field supported by a disk pack are presented, in which full coupling between the gas phase, the condensed phase, and the retreating nonplanar propellant surface is accounted for.

关键词： Heterogeneous Solid Propellant Aluminum Combustion Number of Particles Scatter Plot parallel computing environment Navier Stokes Equations Reaction Rate Constant Universal Gas Constant Thermal Properties Surface Properties

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parallel computations of high-lift airfoil flows using two-equation turbulence models

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AIAA JOURNAL 2000年第8期38卷 1360-1368页

作者： Kim, CS Kim, C Rho, OH Seoul Natl Univ Dept Aerosp Engn Seoul 151742 South Korea

Viscous turbulent flows over high-lift airfoils are investigated by using unsteady, incompressible, and compressible Reynolds-averaged Navier-Stokes equations under a parallel computing environment. Compressibility effects can be significant in the leading-edge region of high-lift airfoils with a highly loaded element. Thus, both the Incompressible and compressible computations are performed to study the compressibility effects. The compressible code involves an upwind-differenced scheme for the convective terms and a lower-upper symmetric Gauss-Seidel scheme for temporal integration. The incompressible code with a pseudocompressibility method also adopts the same schemes as the compressible code. Both codes are parallel processed by using message passing interface programming method and show good parallel speedups. Three two equation turbulence models (the standard k-epsilon, the k-omega, and the k-omega shear stress transport model) are carefully evaluated by computing the flows over single-element and multielement airfoils. The compressible and incompressible codes are validated by predicting the flow around the RAE 2822 transonic airfoil and NACA 4412 airfoil, respectively. In addition, both the incompressible and compressible codes using the Chimera overlapping grid scheme are used to compute the how over the NLR 7301 airfoil with Rap and the NASA GAW-1 high-lift airfoil. Compressibility effects on surface pressure coefficients, velocity profiles, and skin friction coefficients are numerically simulated.

关键词： Turbulence Models Freestream Mach Number NACA 4412 Leading Edge Slat Message Passing Interface Reynolds Averaged Navier Stokes Compressibility Effect Skin Friction Drag parallel computing environment Shear Stress

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Toward cost-effective aeroelastic analysis on advanced parallel computing systems

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JOURNAL OF AIRCRAFT 1999年第4期36卷 710-715页

作者： Goodwin, SA Weed, RA Sankar, LN Raj, P Lockeed Martin Aeronaut Syst Computat Fluid Dynam Flight Sci Div Marietta GA 30063 USA Mississippi State Univ Natl Sci Fdn Res Ctr Computat Field Simulat Nichols Res Inc Vicksburg MS 39180 USA Georgia Inst Technol Sch Aerosp Engn Atlanta GA 30332 USA

Progress toward the development and validation of a fast, accurate, and cost effective aeroelastic method for several advanced parallel computing platforms is presented. The ENSAERO code, developed at NASA Ames Research Center, was selected for this research effort. To improve the performance, the capabilities of the constituent modules have been enhanced. The relative merits of four parallel computing environments are investigated: SGI workstation cluster, SGI Power Challenge machine, SGI Power Challenge cluster, and the IBM SP2 system. To assess the computational performance of the enhanced ENSAERO code, the results of unsteady Navier-Stokes simulations of the transonic how over a fully flexible aeroelastic arrow-wing body configuration are reported. In addition, to ensure that the modified version of ENSAERO performs to specifications and to evaluate the benefits of the enhancements, unsteady Euler/Navier-Stokes calculations for an AGARD standard aeroelastic configuration are done. To evaluate the level of accuracy of the enhanced system, the ENSAERO results are compared with established computational solutions and experimental data.

关键词： Dynamic Aeroelastic Analysis parallel computing Systems parallel computing Platform Freestream Mach Number Navier Stokes Calculations Dynamic Pressure NASA Langley Research Center parallel computing environment Angle of Attack CFL3D

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parallel processing scheme for the Navier-Stokes equations - Part 2: parallel implementation

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AIAA JOURNAL 1998年第11期36卷 2020-2026页

作者： Ghizawi, N Abdallah, S Univ Cincinnati Dept Aerosp Engn & Engn Mech Cincinnati OH 45221 USA

parallel performance of two implicit schemes for solving the compressible Navier-Stokes equations on two parallel computational platforms using the standard (portable) message passing interface is studied. These two schemes are a lower-upper cycle-independent scheme developed by the authors and the symmetric successive overrelaxation scheme (representative of cycle-dependent schemes). The parallel computational platforms used here are the Lewis advanced cluster environment, which is an example of a network of workstations, and the Ohio supercomputer Gray T3D massive parallel computing environment. Two versions of the lower-upper Cycle-independent scheme are studied: version I, where one processor per block is used, and version II, where two processors per block are used. However, only version I is possible with the symmetric successive overrelaxation scheme. The competitiveness of the workstation cluster to the Gray T3D is demonstrated. Moreover, parallel performance results indicate that version I of the lower-upper cycle-independent scheme is superior to version II in the range of a moderate number of processors. However, in the future, as the number of processors increases and the communication cost decreases, this scheme will provide a means for using larger computational power (relative to version I) that would otherwise be idle.

关键词： Navier Stokes Equations Message Passing Interface parallel computing environment Supercomputers Biplane Angle of Attack parallel Computers NACA 0012 NASA Lewis Research Center Asynchronous Transfer Mode

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