2차원 압축성 유동 해석자의 OpenACC를 이용한 GPU 활용

Abstract

A two-dimensional compressible flow solver was ported to GPU using OpenACC. The performance of this program was tested in three cases: viscous flow on a flat plate, inviscid transonic flow in a channel with a bump, and inviscid transonic flow around n0012 airfoil. The GPU program running on RTX 3090 showed up to 20 times of speedup compared to the original program using a single core of Ryzen 5950X, and up to 10 times of speedup compared to the program that uses all resources on the CPU. Among the computation steps of the program, implicit residual smoothing was the worst performing step on the GPU. To address this problem, skipping residual smoothing and using the Cyclic Reduction algorithm were tried as alternatives. These approaches improved speedup in almost every case, increasing the maximum speedups to 24 times compared to the single core program and 11 times compared to the 16-core program. The results show that GPU is a suitable tool for accelerating CFD solvers due to its memory bandwidth and parallel computing capability and using OpenACC is a viable method for porting programs to GPU.