OpenSBLI v3.0: High-fidelity multi-block transonic aerofoil CFD simulations using domain specific languages on GPUs

OpenSBLI is an automatic code-generation framework for compressible Computational Fluid Dynamics (CFD) simulations on heterogeneous computing architectures (previous release: Lusher et al. (2021) [4]). OpenSBLI is coupled to the Oxford Parallel Structured (OPS) Domain Specific Language (DSL), which uses source-to-source translation to enable parallel execution of the code on large-scale supercomputers, including multi-GPU clusters. To date, OpenSBLI has largely been applied to compressible turbulence and shock-wave/boundary-layer interactions on very simple geometries comprised of single mesh blocks with essentially orthogonal grid lines. OpenSBLI has been extended in this new release to target strongly curvilinear cases, including transonic aerofoils using multi-block grids. In addition to multi-block mesh support, more efficient numerical shock-capturing methods and filters have been added to the codebase. Improvements to post-processing, reduced-dimension data output, and coupling to a modal decomposition library are also included. A set of validation cases are presented to showcase the new code features. Furthermore, state-of-the-art wide-span transonic aerofoil simulations on up to N = 2.5 x 10^9 grid points demonstrate that wider aspect ratios can alter buffet predictions and increase the regularity of the low-frequency shock oscillations by accommodating fully-developed trailing edge flow separation. Spectral Proper Orthogonal Decomposition (SPOD) analysis showed that overly-narrow aerofoil simulations contain additional domain-dependent energy content at a Strouhal number of St ≈ 3 associated with wake modes.

OpenSBLI 是一款面向异构计算架构下可压缩计算流体动力学（Computational Fluid Dynamics，CFD）仿真的自动代码生成框架（此前版本参见Lusher等人2021年的研究文献[4]）。OpenSBLI 与牛津并行结构化领域专用语言（Oxford Parallel Structured Domain Specific Language，OPS DSL）耦合，该语言采用源到源编译转换技术，可实现代码在包括多GPU集群在内的大规模超级计算机上的并行执行。迄今为止，OpenSBLI 主要应用于由单网格块、基本正交网格线构成的简单几何构型下的可压缩湍流与激波/边界层相互作用研究。本新版本中对OpenSBLI进行了扩展，使其能够适配强曲线构型仿真场景，包括采用多块网格的跨音速翼型仿真。除新增多块网格支持外，代码库还新增了更高效的数值激波捕捉方法与滤波器。此外，还对后处理、降维数据输出以及模态分解库耦合功能进行了优化升级。文中展示了一组验证案例，以演示新增的代码功能。此外，针对多达2.5×10^9个网格点的当前最先进大展弦比跨音速翼型仿真结果表明，更大的展弦比可通过充分发展的尾缘流动分离，改变气动抖振预测结果，并提升低频激波振荡的规律性。谱本征正交分解（Spectral Proper Orthogonal Decomposition，SPOD）分析显示，展弦比过小的翼型仿真会在斯特劳哈尔数St≈3处出现额外的与计算域相关的能量分量，该分量与尾迹模态相关。