A scalable multi-GPU solver for direct numerical simulation of boundary layer flow*

A flow solver scalable on multiple Graphics Processing Units (GPUs) for direct numerical simulation of boundary layer flow is presented. The solver utilizes a previously reported work (J. Comp. Physics, vol. 352 (2018), pp.246-264) which proposes a semi-implicit fractional-step method on a single GPU. Extension of this work to accommodate multiple GPUs is found to be difficult mainly due to global transpose required in the Alternating Direction Implicit (ADI) and Fourier-transform-based direct methods. The present study suggests a new strategy for designing a multi-GPU solver by applying an algorithm known as the Parallel Diagonal Dominant (PDD) method to the previous work. Implementation details and performance results are compared with those of a flow solver using global transpose. Results from test simulations of turbulent and transitional boundary layer on multiple Tesla P100 GPUs are presented.