Numerical prediction of a plume diffusion field around a circular cylinder by the particle method

Abstract

In order to elucidate the applicability of particle methods to the prediction of diffusion of matter in free turbulent flow, a point-source plume diffusion field upstream of, around and behind a circular cylinder in turbulent flow is simulated. The velocity field is calculated by a vortex method, while the concentration field is computed by a particle method analogous to the vortex method. The calculated mean concentration field from a point source can be favorably discretized by the concentration elements with a finite core. The diffusing matter is entrained into the Kármán vortices and exhibits meandering behavior in accordance with the experiment. The mean concentration is in good agreement with the experiment upstream of, around and behind the cylinder, suggesting that the present particle method has high applicability to the analysis of the mean concentration field.