Yoshinobu Yamade

Prediction of flow field and aerodynamic noise of jet fan using large eddy simulation

To conduct a product development of turbomachinery continuously and developmentally, an approach using large eddy simulation (LES) should be one of the mainstream, because it is already essential to utilize computational fluid dynamics (CFD) using Reynolds averaged Navier–Stokes Simulation in industrial field. In recent years, the demand for a high-efficiency and low-noise jet fan, which is used for ventilation of a tunnel of a carriage way, is getting higher and higher. However, to conduct noise prediction of the jet fan with high accuracy, it needs the high-performance computing technique using a supercomputer. In this study, CFD of the jet fan is conducted using LES. Noise simulation is also conducted using the LES result. Moreover, the fine mesh model is generated by refining a coarse mesh, and LES is conducted using the Earth Simulator. The result of surface pressure using the fine mesh is clearer than the one using the coarse mesh.Graphical abstract

Performance improvement of the general-purpose CFD code FrontFlow/blue on the K computer

The general-purpose fluid simulation software FrontFlow/blue (FFB) is based on the finite element method (FEM). It was designed to accept extremely large-scale simulations and is an important application in the manufacturing field in Japan. Moreover, since this application is significant in both the manufacturing field and the development of the post-K supercomputer, it is employed as an important application for the new post-K supercomputer that is under development. The K computer is still the important infrastructure in Japan. And there are some supercomputers having the same architecture to the K computer. Therefore we continue to improve the performance of the FFB on the K computer. On significant subroutines, several improvement techniques, store order based loop modification decreasing total load and store operations, unrolled loop rerolling to employ SIMD load instruction, adjusting number of arrays in loop, using sector cache function, and so on, were employed. As a result, an improvement of 160% was obtained on a single CPU performance. This paper shows and discusses the detail of these improvements.