Quantifying the interaction between adjacent multiple downbursts, plumes and jets in crossflow and studies of near-wall flows with obstacles

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The interaction between closely spaced jets or plumes features in numerous engineering processes and yet the constructive or destructive mixing that takes place is not predicted very well by most engineering computational fluid mechanics models, resulting in engineering processes that are not optimized, for example the extent to which pollutants are dispersed. This is partly an inherent weakness of those models and partly the lack of detailed flow field data from a sufficient number of configurations to explain these interactions. Of urgent interest is the fact that damage to buildings and structures due to thunderstorm downbursts is a frequent occurrence in Canada and is likely become more common worldwide as a result of climate change. The proposed equipment is essential if the applicant is to successfully carry out his NSERC Discovery research program on these density-driven events and determine the relationship between the initial forcing and the structure and intensity of the near ground outflow winds for isolated and multiple downbursts. The request is for a unique liquid flow facility that, for the first time, allows examination of the interaction between multiple downbursts, rather than only examining single events in isolation. Furthermore, the test equipment will simulate more realistic meteorological conditions than in any previous studies because the downburst sources will be density-driven and translated within a crossflow. Together with the flow equipment a laser induced fluorescence (LIF) system is requested for mapping out scalar fields associated with the fluid density changes in the evolving downbursts and for determining the extent of the mixing between multiple jets and plumes in a crossflow. Both pieces of equipment will be used for other research, notably a large collaborative program (with U Calgary and Saskatchewan) to understand the vortex-dominated wakes of 3-D surface mounted obstacles. The proposed equipment will support the co-applicant's related work in the field of flow over complex surface topography (including vortex generators in heat exchangers) and through ground roughness arrays that represent urban areas, the latter being an area in which the applicant has also been active.