A wind-tunnel simulation of plume dispersion within a large array of obstacles

The dispersion of tracers within a large array of obstacles is investigated in a boundary-layer wind-tunnel simulation. The experiment models at 1:50 scale a large outdoor field study that simulated an urban boundary layer with an array of shipping containers, known as MUST (Mock Urban Setting Test - Yee and Biltoft, 2004, Boundary-Layer Meteorology 111, 363-415). The wind-tunnel results are reported and discussed in detail, and some comparisons are drawn to the outdoor field trial and previous studies of plume dispersion within obstacle arrays, as well as open terrain. The analysis covers a wide range of concentration statistics and other quantitative descriptors of plume behaviour, giving a comprehensive treatment of the physical mechanisms involved in the development of a dispersing plume within an 'urban-like' environment. Emphasis is placed on the description and mathematical modelling of concentration fluctuations within the plume, as well as the usual mean concentration results. Some discussion is also centred on the physical similarities and differences between scaled model simulations and full-scale dispersion experiments, and some possibly surprising influences of upwind flow conditioning on obstacle array dispersion that require more careful attention[PUBLICATION ABSTRACT]