GPU-accelerated large-scale simulations of interfacial multiphase fluids for real-case applications

•A new CFD model for large scale simulations of multi-phase flows on GPU computers.•Numerical formulation well-balancing accuracy and computational efficiency.•The first ever report on the real-case direct simulations of whole flush toilet systems.•A practical and innovative tool for designing water-saving sanitary ware products.

This paper presents a newly developed numerical model to simulate interfacial multi-phase flows in sanitary wares with high grid resolutions on Graphics Processing Unit (GPU)-equipped supercomputer. The numerical methods, including both interface capturing scheme and multi-phase fluid solver, are devised with high accuracy over compact computational stencil so as to be computationally efficient and well-suitable for hardwares of multi-core CPUs with many-core GPU accelerators. The code has been entirely ported to such a system using CUDA-driver API and MPI libraries to make fully possible use of the GPU acceleration capability on large-scale parallel computations. The high-resolution simulations with large number of mesh elements on the “TSUBAME” supercomputer, a GPU-rich system in Tokyo Institute of Technology, were conducted to simulate, for the first time, a whole sanitary ware with a mesh resolution of 1/10-mm level. Numerical results show that the present numerical model provides an innovative and practical CAE tool for the design process of water-saving sanitary ware products.