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

密集的射流或羽流之间的相互作用在许多工程过程中具有特征，但大多数工程计算流体力学模型不能很好地预测所发生的建设性或破坏性混合，导致工程过程未被优化，例如污染物分散的程度。这部分是这些模型固有的弱点，部分是缺乏足够数量的配置来解释这些相互作用的详细流场数据。迫切感兴趣的是，由于雷暴下击暴流对建筑物和结构的破坏在加拿大经常发生，并且由于气候变化，在世界范围内可能变得更加普遍。如果申请人要成功地对这些密度驱动的事件进行NSERC发现研究计划，并确定孤立和多个下击暴流的初始强迫与近地外流风的结构和强度之间的关系，则拟议的设备是必不可少的。该请求是一个独特的液体流动设施，第一次，允许检查多个下击暴流之间的相互作用，而不是只检查孤立的单个事件。此外，测试设备将模拟比以往任何研究更真实的气象条件，因为下击暴流源将是密度驱动的，并在横流中平移。连同流动设备的激光诱导荧光（LIF）系统被要求映射出标量场与流体密度的变化，在不断发展的下击暴流，并确定在横流中的多个射流和羽流之间的混合程度。这两件设备将用于其他研究，特别是一个大型合作项目（与卡尔加里大学和萨斯喀彻温省），以了解三维表面安装障碍物的涡主导尾流。拟议的设备将支持共同申请人在复杂表面地形（包括热交换器中的涡流发生器）上的流动和通过代表城市地区的地面粗糙度阵列的流动领域的相关工作，后者是申请人也一直积极参与的一个领域。

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.