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International Conference on Advanced Materials in Microwaves and Optics (AMMO 2011)

作者： Zeng, Xiaohui Liu, Dongsheng Luo, Wenlang Fu, Lixin School of Electronics and Information Engineering Jinggangshan University China Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University China

ISBN: (纸本)9783037852736

In order to apply our high efficiency fibre-channel token-routing network (shortened as FC-TR network) to the field of materials simulation research, a new MPI parallel computing environment is proposed and designed, and independently developed a parallel programming environment FC-TR-MPI based on FC-TR network. In FC-TR-MPI, a new method was applied to point-to-point communication that the network communications between processes in the same computing node were changed into memory operations;moreover, according to the underlying software and hardware features of FC-TR network, new algorithms were proposed to optimize the communication performance of some collective communications. Experimental results show that, compared with ScaMPI parallel programming environment, FC-TR-MPI has a higher parallel efficiency and speedup.

关键词： MPI parallel computing environment fibre-channel materials simulation

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

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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 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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Refined Numerical Simulation of Three-Dimensional Riveting in Laminated Composites

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JOURNAL OF AIRCRAFT 2011年第4期48卷 1434-1443页

作者： Yoon, Tae Ho Kim, Seung Jo Seoul Natl Univ Sch Mech & Aerosp Engn Seoul 151744 South Korea

Riveting in laminated composites is not carried out, because the riveting process can easily induce failure and form a nonuniform interference fit. An electromagnetic riveting riveter provides a relatively uniform interference fit with no direct failure in the riveted joint. Finite element numerical simulation of three-dimensional riveting is conducted by considering the sine wave of force history for the electromagnetic riveting riveter. To reflect the physical phenomenon of the complicated contact of riveting in laminated composites, a refined modeling of the washer inner fillet is considered, and the parallel computations using LS-DYNA are used. Refined simulation is validated by experiments reported in the literature. The electromagnetic riveting is properly applied for riveting in laminated composites. Optimized maximum riveting force is obtained for relative uniform interference based on the criterion of relative interference for fatigue life extension. A parametric study of the washer effects during the riveting process is investigated to obtain a proper riveted joint in laminated composites.

关键词： Fiber Volume Fraction Numerical Simulation Maximum Shear Stresses Composite Structures Fatigue Life parallel computing environment parallel computing Systems Numerical Analysis Yield Stress computing Technology

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parallel computing USING SEMIANALYTICAL FINITE-ELEMENT METHOD

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AIAA JOURNAL 1994年第5期32卷 1066-1071页

作者： KIM, JR KIM, WD KIM, SJ Seoul National University Seoul 151-742 Republic of Korea

In this paper, a parallel computing technique using a semianalytical finite element method and its implementation method are studied, and the speedup in the elapsed computing time is discussed. The structural analysis of an axisymmetric body with nonaxisymmetric boundary conditions is considered by using a semianalytical finite element method. The displacements and the boundary conditions are expressed by a Fourier series. By the orthogonality properties of the Fourier series, the equilibrium equations are fully decoupled for each mode. Therefore, these decoupled equations can be well adapted to the individual processors of a parallel computer. Two example problems are considered for the verification of the developed code and for the application of the parallel processing to practical problems. The computing time by parallel processing is compared with that by sequential processing, and a large amount of improvement in the elapsed computing time is achieved by parallel processing. From the computational experiments, a speedup of 4.6 times in elapsed time is observed with six processors of Alliant FX2812 at Seoul National University.

关键词： Finite Element Analysis parallel computing environment parallel computing Techniques parallel Computers Structural Analysis Abaqus Stress Distribution Cantilever Beam FORTRAN Composite Structures

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parallel computational fluid dynamics design on network-based computer

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JOURNAL OF AIRCRAFT 1996年第3期33卷 561-566页

作者： Cheung, SS NASA AMES RES CTR MOFFETT FIELDCA 94035

Combining multiple engineering workstations into a network-based heterogeneous parallel computer allows the application of aerodynamic optimization with advanced computational fluid dynamics codes, which can be computationally expensive on mainframe supercomputers. This article introduces a nonlinear quasi-Newton optimizer designed for this network-based heterogeneous parallel computing environment utilizing a software called parallel Virtual Machine. This article will introduce the methodology behind coupling a parabolized Navier-Stokes flow solver to the nonlinear optimizer. This parallel optimization package is applied to reduce the wave drag of a body of revolution and a wing/body configuration with results of 5-6% drag reduction.

关键词： CFD Analysis Aerodynamic Design Wing Body Configuration parallel Computers Supercomputers parallel computing environment Computational Fluid Dynamics Code Newton's Method Fuselages Method of Steepest Descent

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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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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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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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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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