Enhancements to Overset Methods for Improved Accuracy and Solution Convergence

Sitaraman, Jayanarayanan; Jude, Dylan; Brazell, Michael

doi:10.2514/6.2020-1528

Cited by 6 publications

(2 citation statements)

References 38 publications

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“…But these employ either simple analytical solutions 18,19 which are far from the desired practical applications, or use industrial cases where the emphasis is validation. 8,[18][19][20] Due to the inherent complexity, numerical and modeling errors are then entangled and therefore difficult to quantify. Moreover, in these papers, a small number of interpolation techniques are studied and rarely are accuracy, convergence order, robustness, and computational performance simultaneously and comprehensively analyzed.…”

Section: Introductionmentioning

confidence: 99%

On the accuracy, robustness, and performance of high order interpolation schemes for the overset method on unstructured grids

Lemaire

Vaz

Rijswijk

et al. 2021

Numerical Methods in Fluids

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A comprehensive study on interpolation schemes used in overset grid techniques is here presented. Based on a literature review, numerous schemes are implemented, and their robustness, accuracy, and performance are assessed. Two code verification exercises are performed for this purpose: a 2D analytical solution of a laminar Poiseuille steady flow; and an intricate manufactured solution of a turbulent flow case, characteristic of a boundary layer flow combined with an unsteady separation bubble. For both cases, the influence of grid layouts, grid refinement, and time-step is investigated. Local and global errors, convergence orders, and mass imbalance are quantified. In terms of computational performance, strong scalability, cpu timings, load imbalancing, and domain connectivity information (DCI) overhead are reported. The effect of the overset-grid interpolation schemes on the numerical performance of the solver, that is, number of nonlinear iterations, is also scrutinized. The results show that, for a second order finite volume code, once diffusion is dominant (low Reynolds number), interpolation schemes higher than second order, for example, least squares of degree 2, are needed not to increase the total discretization errors. For convection dominated flows (high Reynolds numbers), the results suggest that second order schemes, for example, nearest cell gradient, are sufficient to prevent overset grid schemes to taint the underlying discretization errors. In terms of performance, by single-process and parallel communication optimization, the total overset-grid overhead (with DCI done externally to the CFD code) may be less than 4% of the total run time for second-order schemes and 8% for third-order ones, therefore empowering higher-order schemes and more accurate solutions.

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Section: Introductionmentioning

confidence: 99%

On the accuracy, robustness, and performance of high order interpolation schemes for the overset method on unstructured grids

Lemaire

Vaz

Rijswijk

et al. 2021

Numerical Methods in Fluids

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show abstract

“…WAKE3D has been demonstrated on various aerodynamics problems [14] and wind energy applications [15]- [18]. The framework is composed of multiple software components, namely, NSU3D [19], DG4EST [16], [20], and TIOGA [21], [22]. Figure 1 illustrates the simulation of a Siemens SWT-2.3-93 wind turbine using WAKE3D.…”

Section: Cpu Implementationmentioning

confidence: 99%

GPU-Accelerated Discontinuous Galerkin Methods: 30x Speedup on 345 Billion Unknowns

Kirby¹,

Mavriplis²

2020

Preprint

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A discontinuous Galerkin method for the discretization of the compressible Euler equations, the governing equations of inviscid fluid dynamics, on Cartesian meshes is developed for use of Graphical Processing Units via OCCA, a unified approach to performance portability on multi-threaded hardware architectures. A 30x speedup over CPU-only implementations using non-CUDA-Aware MPI communications is demonstrated up to 1,536 NVIDIA V100 GPUs and parallel strong scalability is shown up to 6,144 NVIDIA V100 GPUs for a problem containing 345 billion unknowns. A comparison of CUDA-Aware MPI communication to non-GPU-direct communication is performed demonstrating an additional 24% speedup on eight nodes composed of 32 NVIDIA V100 GPUs.

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Direct Flux via Virtual Faces (DFVF-overset): Interpolation-free, conservative, overset CFD using a generalised finite volume method

Devlin,

Chandar,

Quinlan

2023

Computers & Fluids

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Enhancements to Overset Methods for Improved Accuracy and Solution Convergence

Cited by 6 publications

References 38 publications

On the accuracy, robustness, and performance of high order interpolation schemes for the overset method on unstructured grids

On the accuracy, robustness, and performance of high order interpolation schemes for the overset method on unstructured grids

GPU-Accelerated Discontinuous Galerkin Methods: 30x Speedup on 345 Billion Unknowns

Direct Flux via Virtual Faces (DFVF-overset): Interpolation-free, conservative, overset CFD using a generalised finite volume method

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