Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 03, 2018
In order to investigate the modulation of turbulence structures in boundary layers on various rough walls, direct numerical simulations were performed by solving the fundamental equations with external forces by roughness on a wall. As a result, in the case that the height of the roughness is smaller than the border of the viscous sublayer and buffer layer, the turbulence structures similar to those on a smooth wall could be observed. In contrast, in the case that the height is larger than the buffer layer, the characteristics of turbulence structures drastically changed. We propose a new normalization method in which we can observe universally the spatial features of turbulence structures on a rough wall. This means that, by using the proposed method, the knowledge for wall turbulence obtained in past studies can be applied to the case of turbulent flow along a rough wall.
