Direct Numerical Simulation of a Turbulent Channel Flow by Vortex in Cell Method

Abstract

Direct numerical simulation (DNS) for a turbulent channel flow is performed by the Vortex in Cell (VIC) method. The Reynolds number based on the friction velocity and the channel half width is 180. The improvements for the VIC method proposed in the prior study are used. Staggaerd grid is employed to ensure the consistency between the discretized equations as well as to prevent the numerical oscillation of the solution. A method correcting the vorticity is used so that the resultant vorticity field satisfies the solenoidal condition. A single-stage calculation method for the convection of vortex element is also utilized to reduce the computational time. The simulated turbulence statistics such as the mean velocity, the turbulence intensity and the Reynolds shear stress are favorably compared with the existing DNS results. The streak structures and the streamwise vortices near the wall are also successfully captured. These computational results demonstrate that the improved VIC method is indeed applicable to the DNS of wall turbulence simulations.