ABSTRACT The focus of this study is to numerically reproduce the asynchronous oscillations of an impinging slot jet on a concave surface experimental configuration. A Detached Eddy Simulation (DES) numerical simulation was realised at a Reynolds number of with respect to the slot jet width. The topological characteristics of the flow were also analyzed using the Proper Orthogonal Decomposition (POD) method. It was therefore possible to propose a sequence of flow topologies (four distinct flow states) during the changeover phenomenon of the impinging slot jet. The results show that the asynchronous phenomenon of the impinging slot jet seems to be related to the transitional characteristics of the jet flow. The flow topology of the most stable and energetic states (top and bottom jet flow states) creates a pressure imbalance inside the area of interest, resulting in the appearance of two transitional flow states. For the top or bottom impinging jet flow states, the jet remains in a relatively stationary position and the flow in the area of interest is quasi-two-dimensional. However, during the rapid changeover of the jet between these two states, small vortex structures prevail inside the area of interest for the centre jet states.

中文翻译：

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凹面撞击射流异步现象的气动分析

摘要 本研究的重点是在凹面实验配置上以数值方式再现撞击槽射流的异步振荡。分离涡流模拟 (DES) 数值模拟是在雷诺数相对于狭缝射流宽度的情况下实现的。流动的拓扑特征也使用适当的正交分解 (POD) 方法进行了分析。因此，可以在撞击狭缝射流的转换现象期间提出一系列流动拓扑（四种不同的流动状态）。结果表明，撞击狭缝射流的异步现象似乎与射流的过渡特性有关。最稳定和能量状态（顶部和底部喷射流状态）的流动拓扑在感兴趣区域内产生压力不平衡，导致出现两种过渡流动状态。对于顶部或底部撞击射流流动状态，射流保持在相对静止的位置，并且感兴趣区域中的流动是准二维的。然而，在这两种状态之间的射流快速转换期间，中心射流状态的感兴趣区域内普遍存在小涡流结构。