Parallel and scalable custom computing for real-time fluid simulation on a cluster node with four tightly-coupled FPGAs

Numerical simulation based on computational fluid dynamics (CFD) is now an indispensable technique especially in industry due to its acquisition capability of various data at a lower cost than experiments using a wind tunnel. The lattice Boltzmann method (LBM) is one of the CFD schemes, which is used to compute various problems including multiphase flow. LBM has good parallelism, but simultaneously requires many data to compute each lattice point, resulting in a low operational intensity. Consequently, the sustained performance of LBM is limited by memory bandwidth rather than arithmetic performance when computed by using general-purpose processors and GPUs. To make matters worse, insufficient bandwidth and high-latency of an interconnection network cause a relatively big overhead in parallel computing, especially in the case of strong-scaling.