Eulerian RANS simulations of near-field pollutant dispersion around buildings using concentration diffusivity limiter with travel time

To improve the prediction accuracy of pollutant dispersion near a source, limiter for turbulent concentration diffusivity accounting travel time is introduced into Reynolds-averaged Navier–Stokes equations (RANS) and Eulerian model. We predict in two-dimensional street canyon three-dimensional building arrays via conventional modeling based on simplified gradient diffusion hypothesis limiter. The results are validated using data from wind tunnel experiment. Conventional with Sct=0.3 yields similar to experimental results. However, mean source underestimated. reduces by adjusting combination model parameters improves prediction. Based result limiter, we discovered that Schmidt number definition can exceed three times downwind region. Finally, discuss effect net mass fluxes removal. For arrays, increases advective flux transports more pollutants toward leeward wall, thereby decreasing surface-sum spanwise turbulent-mass-flux at source-located side.