Direct numerical simulations of turbulent channel flow with wall transpiration using lattice Boltzmann method

Direct numerical simulations of turbulent channel flow with wall transpiration are conducted using the multi-relaxation time lattice Boltzmann method for the first time. Flows with two friction Reynolds numbers, $Re_\tau$ = 150 and 250, are investigated, and the explored transpiration rates based on the friction velocity range from 0.05 to 0.26. A successive block mesh-refinement strategy is adopted to resolve the near-wall structure, where the grid sizes are $\Delta <^>+ \sim$1, 2, and 4. Under such resolution, the size of the maximum grid density employed is $775 \times 10<^>6$. At the low transpiration rate ($V<^>+=0.05$), the turbulence level at the suction side is damped relative to the less altered values along the injection side. However, at the high level of wall transpiration, i.e. $V<^>+=0.26$, turbulence levels are severely retarded on both the injection and suction sides. The predicted mean and turbulence quantities show good agreements with the available direct numerical simulation data, indicating the effectiveness of lattice Boltzmann method combined with mesh refinement in reproducing the correct physics of turbulent channel flows with different levels of wall transpiration.