Efficient Aerodynamic Shape Optimization

Jameson, Antony

doi:10.2514/6.2004-4369

Cited by 42 publications

(32 citation statements)

References 33 publications

(33 reference statements)

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“…SYN83 [20] uses a continuous adjoint to the two-dimensional (2-D) Euler equations to compute the gradient of the objective function with respect to the design space. Here, the design space is automatically generated by SYN83; it corresponds to the highestdimensional space supported by the discrete points of the grid defining the geometry.…”

Section: Aerodynamic Optimization Methodsmentioning

confidence: 99%

Study Based on the AIAA Aerodynamic Design Optimization Discussion Group Test Cases

et al. 2015

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Three model problems associated with aerodynamic drag minimizations are studied. These test cases have been proposed by the aerodynamic design optimization discussion group, and they include an inviscid NACA0012 nonlifting airfoil, a viscous RAE2822 lifting airfoil, and a viscous lifting wing based on the NASA Common Research Model. Various optimization methods are used, including MDOPT, TRANAIR, SYN83, and SYN107. The resulting designed and associated baseline geometries are cross analyzed by several computational fluid dynamics codes, including OVERFLOW, TRANAIR, GGNS, and FLO82. Pathological issues are unveiled in both of the simple airfoil model problems. Designed geometries for the inviscid symmetric test case exhibit strong tendencies to permit nonsymmetric flow solutions. Designed airfoils for the viscous lifting case also support nonunique solutions and hysteresis loops at or near the design point in Reynolds-averaged Navier-Stokes and integral boundary-layer method simulations. These results provide further evidence that single-point aerodynamic optimization is often ill posed. In extreme cases, it can yield designs with very undesirable aerodynamic characteristics, at least as analyzed by Reynolds-averaged Navier-Stokes and integral boundary-layer methods occurring at offdesign, and even ondesign, conditions. These examples are used to further document the multiple-solution and pseudosolution phenomena for steady-state Reynolds-averaged Navier-Stokes. This provides evidence that, even in practical engineering settings, numerical methods to assess stability and uniqueness of steady-state solutions and/or predict the bifurcations of these solutions have value. The single-point wing design problem is likewise ill posed in the spanwise direction. A multipoint design with a potentially large number of points or the inclusion of inequality constraints can regularize the problem.wing reference chord, which is approximately equal to the mean aerodynamic chord M = Mach number; V∕a P 0 = total pressure q = dynamic pressure; 1 2 ρV 2 Re = Reynolds number; ρ ∞ V ∞ C ref ∕μ ∞ S ref = reference area t = thickness of an airfoil α = angle of attack Δ = difference in quantity (new-baseline) η = fraction of wing semispan κ = curvature ρ = radius of curvature τ = trailing-edge-included angle ∞ = freestream conditions

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Section: Aerodynamic Optimization Methodsmentioning

confidence: 99%

Study Based on the AIAA Aerodynamic Design Optimization Discussion Group Test Cases

et al. 2015

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“…The original formulation preserves the hyperbolic nature of the system, but destroys time accuracy. A common procedure for recovering time accuracy is dual time stepping [13]. In this approach, real time is discretised with a backward difference scheme, whose solution is found by marching the governing equation in pseudo time.…”

Section: Introductionmentioning

confidence: 99%

A high-order cross-platform incompressible Navier–Stokes solver via artificial compressibility with application to a turbulent jet

Loppi

Witherden

Jameson

et al. 2018

Computer Physics Communications

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a b s t r a c tModern hardware architectures such as GPUs and manycore processors are characterised by an abundance of compute capability relative to memory bandwidth. This makes them well-suited to solving temporally explicit and spatially compact discretisations of hyperbolic conservation laws. However, classical pressure-projection-based incompressible Navier-Stokes formulations do not fall into this category. One attractive formulation for solving incompressible problems on modern hardware is the method of artificial compressibility. When combined with explicit dual time stepping and a high-order Flux Reconstruction discretisation, the majority of operations can be cast as compute bound matrix-matrix multiplications that are well-suited for GPU acceleration and manycore processing. In this work, we develop a high-order cross-platform incompressible Navier-Stokes solver, via artificial compressibility and dual time stepping, in the PyFR framework. The solver runs on a range of computer architectures, from laptops to the largest supercomputers, via a platform-unified templating approach that can generate/compile CUDA, OpenCL and C/OpenMP code at runtime. The extensibility of the cross-platform templating framework defined within PyFR is clearly demonstrated, as is the utility of P-multigrid for convergence acceleration. The platform independence of the solver is verified on Nvidia Tesla P100 GPUs and Intel Xeon Phi 7210 KNL manycore processors with a 3D Taylor-Green vortex test case. Additionally, the solver is applied to a 3D turbulent jet test case at Re = 10,000, and strong scaling is reported up to 144 GPUs. The new software constitutes the first high-order accurate cross-platform implementation of an incompressible Navier-Stokes solver via artificial compressibility and P-multigrid accelerated dual time stepping to be published in the literature. The technology has applications in a range of sectors, including the maritime and automotive industries. Moreover, due to its cross-platform nature, the technology is well placed to remain relevant in an era of rapidly evolving hardware architectures. Solution method: Artificial compressibility formulation discretised with a high-order Flux Reconstruction approach in space and P-multigrid accelerated dual time stepping in time. Program summary

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“…a good trade-off between the efficacy in representing the features of interest of the flow and the computational time necessary for carrying out the analyses. While the accuracy of the analyses is obviously important to the reliability of the results, a discussion on this topic is outside the scope of this paper; it should be observed that the real challenge-and the practical purpose-of the use of CFD in ASO is to find a shape which performs better than the original shape (Jameson, 2004). Also, the quality of the simulations does not affect the general validity of the method presented.…”

Section: Flow Simulationmentioning

confidence: 91%

Aerodynamic shape optimization of civil structures: A CFD-enabled Kriging-based approach

Bernardini

Spence

Wei

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

110

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a b s t r a c tIn the case of mega-structures such as tall buildings and long-span bridges, the mitigation of the intensity of the wind excitation through aerodynamic tailoring of the external shape can be fundamental for meeting the performance goals. The search for the best performing shape through an automatic CFD-enabled optimization methodology is potentially less expensive, less time-consuming and more thorough than the common trial-and-error approach based on wind tunnel test results, therefore very attractive. This paper investigates the possibility of carrying out the multi-objective aerodynamic shape optimization of civil structures through an approach in which evolutionary algorithms are used in synergy with ordinary Kriging surrogates. A specifically developed strategy is adopted to update the Kriging models making efficient use of additional CFD runs. Shell scripting, parallelized computations and mesh morphing algorithms are exploited for enhancing the framework's efficiency and consistency. As a case study, the optimization of the shape of a tall building cross-section in terms of both the lift and the drag coefficient is considered.

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Efficient Aerodynamic Shape Optimization

Cited by 42 publications

References 33 publications

Study Based on the AIAA Aerodynamic Design Optimization Discussion Group Test Cases

Study Based on the AIAA Aerodynamic Design Optimization Discussion Group Test Cases

A high-order cross-platform incompressible Navier–Stokes solver via artificial compressibility with application to a turbulent jet

Aerodynamic shape optimization of civil structures: A CFD-enabled Kriging-based approach

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