抄録
To investigate the modulation of turbulence structures such as velocity streaks and quasi-streamwise vortices in turbulent boundary layers on various rough walls, direct numerical simulations were carried out by solving the fundamental equations of compressible flow with the external forces which modeled the effect of roughness on a wall. A new spatial scale which introduced the additional effect of the roughness as the wall friction was used to observe the results of the simulations. As a result, if the height of the roughness was within a certain range of the turbulent boundary layer, according to the new scaling, the characteristics of the turbulence structures corresponded with those of the standard scaling for the case of a smooth wall. This means that, in such cases, the knowledge for wall turbulence obtained in the past studies could be applied to the case of turbulent flow along a rough wall.
