Role of spanwise rollers by Kelvin–Helmholtz instability in turbulence over a permeable porous wall

Abstract

Direct numerical simulation over porous walled channel flows with computational domain size constraints were performed to clarify the role of spanwise rollers associated with the Kelvin--Helmholtz instability on turbulent flows over a porous wall. The spanwise rollers contribute to an increase in turbulence inside the porous wall and modify the logarithmic law in the clear flow region.