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

近距离射流或羽流之间的相互作用是许多工程过程的特征，然而大多数工程计算流体力学模型并不能很好地预测发生的建设性或破坏性混合，导致工程过程没有得到优化，例如污染物的分散程度。这部分是这些模型的固有弱点，部分是缺乏足够数量的构型的详细流场数据来解释这些相互作用。令人迫切感兴趣的是，雷暴暴发对建筑物和构筑物的破坏在加拿大经常发生，并可能因气候变化而在世界各地变得更加常见。如果申请者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面流出风的结构和强度之间的关系，建议的设备是必不可少的。这一要求是为了一种独特的液体流动设备，该设备首次允许检查多个下击暴流之间的相互作用，而不是仅孤立地检查单个事件。此外，测试设备将比以往任何研究都模拟更真实的气象条件，因为下暴流来源将是密度驱动的，并在横流中进行转换。与流动设备一起，需要激光诱导荧光(LIF)系统来绘制与演变的下击暴流中的流体密度变化有关的标量场，并确定横流中多个喷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U Calgary和Saskatchewan)，以了解三维表面安装的障碍物的涡流主导的尾流。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)的流动领域以及通过代表城市地区的地面粗糙度阵列开展的相关工作，后者也是申请人一直活跃的领域。

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.