Abstract

Since the advent of supercomputers, numerical simulations for complicated phenomena have been made possible by applying their powerful computational capability. They gave it outstanding contributions to reveal the unknown in the wide variety of science and engineering fields, especially in turbulence.

The spectral method has a large number of floating point operations in kernel loops and therefore requires high memory bandwidth between CPU and memory, as well as CPU performance. Moreover, since data transposition of 3-dimensional data array among parallel elements appears in parallel computation of the method, high bi-sectional bandwidth of inter-element network is also required. Therefore, it is the essential and important method to consider the HPC systems

The recent trend of HPC systems which have more than ten thousand of parallel computational elements with low peak performance and low electricity, however, brings us some difficulties such as fine-grain parallelisation and low efficiency of computation in using HPC systems for the turbulence simulations. Longer simulation time will be requested if the systems have great peak performance like PFLOPS class. The trade-off between high performance capability and low electric power is essential issue in designing the HPC systems.

We will discuss a possibility of higher resolution turbulence simulations by referring a recent trend of HPC systems and a development project of HPC system in Japan.