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通过有限的风洞试验数据,揭示雷诺数效应的发生、发展机理,关键在于找出能够有效表征雷诺数效应的特征参数。以经典圆柱模型为研究对象,在系列雷诺数效应风洞试验基础上,从边界层分离、转捩和旋涡脱落等方面,研究了表征雷诺数效应的气动参数及其数据识别方法。针对经典圆柱模型,采用压力系数时程和压力梯度提取有关边界层分离和流动转捩的物理信息。研究表明,在分离边界层转捩区间内分离点附近的压力系数时程会出现明显的阶跃现象,并伴有骤增的压力梯度值,可作为判定雷诺数转捩区间的辅助方法。为研究不同雷诺数下模型周围主导旋涡的作用特点,采用谱正交分解法(SPT)来识别旋涡作用及其对脉动风压场的能量贡献等,旨在对类似结构的雷诺数效应研究提供参考。
Through limited wind tunnel test data, revealing the occurrence and development mechanism of Reynolds number effect lies in finding the characteristic parameters that can effectively characterize the Reynolds number effect. Based on the series of Reynolds number effect wind tunnel tests, the aerodynamic parameters and their data identification methods which characterize the Reynolds number effect are studied from the aspects of boundary layer separation, transition and vortex shedding. For the classical cylindrical model, the physical information of the boundary layer separation and the flow transition is extracted using the pressure coefficient time history and pressure gradient. The study shows that there is a obvious step-up phenomenon in the pressure coefficient near the separation point in the transition zone of the boundary layer, accompanied by sudden pressure gradient value, which can be used as an auxiliary method to determine the Reynolds number transition zone. In order to study the characteristics of dominated vortices around the model under different Reynolds numbers, the spectral orthogonal decomposition (SPT) is used to identify the vortex and its contribution to the fluctuating wind pressure field, so as to provide the Reynolds number effect of similar structure reference.