Automatic Code-Generation to Enable High-Fidelity Simulations of Multi-Block Airfoils on GPUs

High-fidelity numerical studies of three-dimensional airfoil flows require extremely large scale computational resources. Many of the industry-relevant studies at operating flight conditions over a range of flow-speeds rely on low-fidelity RANS-based solvers to make the computational challenge tractable. In order to perform more accurate scale-resolving simulations, this work describes extensions to a high-fidelity Computational Fluid Dynamics (CFD) solver, OpenSBLI, to target transonic airfoil flows on structured meshes. OpenSBLI is an open-source code-generation system for compressible CFD on heterogeneous computing architectures. OpenSBLI generates a complete CFD solver in the Oxford Parallel Structured (OPS) domain specific language. The OPS library is embedded in C/C++, enabling massivelyparallel execution on various high-performance-computing architectures, including GPUs. As an important step to target critical phases of the flight envelope such as transonic buffet, more computationally efficient shock-capturing methods are added to the code based on a non-linear WENO filtering framework. The methods are shown to have lower numerical dissipation and reduced computational cost compared to other schemes for a supersonic Taylor-Green vortex case. Curvilinear geometries are validated for circular cylinder cases. Finally, high-fidelity airfoil simulations are presented at a Reynolds number of 500,000. A range of sharp and rounded trailing edge configurations are compared to show the effect of trailing edge treatment. The effect of spatial filtering is also shown for code-to-code comparisons of transonic buffet at moderate Reynolds numbers, with good agreement observed with respect to reference data. The present work demonstrates the suitability of code-generation methods and domain specific languages for high-fidelity aerospace research.