摘要

In this paper, turbulent dispersion of a passive scalar released from a ground-level instantaneous point source in a regular array of building-like obstacles is studied. The numerical results for the disturbed flow, scalar concentration and scalar concentration variance are compared with a set of high-quality experimental measurement data. This dataset corresponds to a water-channel simulation of the Mock Urban Setting Trial (MUST). A new dissipation length-scale model proposed by Yee ,i>et al. (Boundary-Layer Meteorol., 30:169−208, 2009) for modelling the scalar dissipation rate is thoroughly investigated in comparison with a conventional integral length-scale based scalar dissipation model. It is demonstrated that with our recommended modifications, the scalar dissipation model of Yee et al. can be successfully used for predicting concentration fluctuation statistics in a cloud (released from a localized source) dispersing in a built-up environment.