Author(s): Keisuke Asakura; Akihiko Nakayama
Linked Author(s): Akihiko Nakayama
Keywords: Turbulent diffusion; Contaminant; LES models; Temperature stratification
Abstract: The concentration field of passive contaminant released in a turbulent boundary layer has been computed by large-eddy simulation (LES) method. The inflow boundary layer with turbulent fluctuations of velocity and temperature was generated using a method similar to that of Lund et al. (1998) and Kong et al. (2000)) of recycling velocity and temperature fluctuations in a driver section placed upstream of the main calculation region. A few different combinations of sub-grid scale (SGS) models for the momentum transfer and the heat and passive scalar fluxes were examined. It was found that the quality of prediction of the diffusion of passive contaminant depends on the accuracy of the calculation of the velocity fluctuations. Differences among various sub-grid models are found to be small but the Mixed-time scale model (MTS) for the sub-grid stresses combined with the dynamic eddy diffusion model was found to give the best results of concentration distribution.
Year: 2011