Computational fluid dynamics and fluid-structure interaction simulations involving moving and deforming bodies is extremely hard. In this work, we present a graphical processing unit (GPU) optimized implementation of the sharp-interface immersed boundary method. The method allows performing simulation around complex stationary as well as moving bodies on a Cartesian grid. We base our implementation on the ViCar3D framework and make use of OpenACC, CUDA, NCCL and MPI. We test the implementation across grid sizes ranging from O(10million) to O(1billion) points and achieved a 20X speedup compared to existing CPU implementation. We next present our multi-GPU implementation by utilizing CUDA streams and NCCL communicators. This enables us to obtain a >90% strong and weak scaling efficiencies. Next we demonstrate the capability of the developed software to simulate a turbulent fluid flow and coupled fluid-structure interaction in flapping bat wing in flight at Re=5000.

翻译：摘要：涉及运动与形变物体的计算流体动力学及流固耦合模拟极为困难。本文提出了一种基于图形处理器（GPU）优化的尖锐界面浸入边界法实现，该方法可在笛卡尔网格上对复杂静止及运动物体进行模拟。我们以ViCar3D框架为基础，结合OpenACC、CUDA、NCCL及MPI实现算法。在网格规模从数千万到十亿量级的测试中，相较于现有CPU实现实现了20倍加速。通过利用CUDA流与NCCL通信器，我们进一步实现了多GPU并行方案，获得了超过90%的强扩展与弱扩展效率。最后，本文展示了所开发软件在扑翼蝙蝠飞行（雷诺数Re=5000）中湍流流动与流固耦合问题的模拟能力。