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针对表面剪切应力不易测量的问题,在南京航空航天大学低速风洞实验室进行了模型表面剪切应力油膜干涉法的研究。试验元件分别为无粗糙元平板和带有可精确控制粗糙元尺寸的柱式转捩带平板。转捩带分布直径为2.5 mm,横向分布间距为10 mm的粗糙元,其中粗糙元高度可调节,本次实验采用1.0 mm和1.5 mm两种高度。试验结果采用MATLAB进行处理;在后续的仿真计算中,采用GAMBIT生成前处理网格,FLUENT进行数值模拟。试验结果表明:无粗糙元平板,应用油膜干涉法测得的表面剪切应力和CFD仿真计算结果较为接近。添加粗糙元后,转捩提前发生,表面摩擦应力增大。油膜干涉法配合可以精确控制粗糙元尺寸的柱式转捩带测量表面剪切应力,可进一步提高风洞试验模型边界层转捩模拟的准确性、可靠性和可操作性。
In order to solve the problem that surface shear stress is not easy to measure, a study on model surface shear stress oil film interference method was carried out in the low speed wind tunnel laboratory of Nanjing University of Aeronautics and Astronautics. The test elements were a plate without roughening plate and a columnar plate with precise control of the size of the roughening element. The transition zone with a diameter of 2.5 mm, the horizontal distribution of the pitch of 10 mm rough elements, including the roughness height adjustable, the experiment using two 1.0 mm and 1.5 mm height. The test results are processed by MATLAB. In the subsequent simulation calculation, GAMBIT is used to generate the preprocessing grid and FLUENT is used for numerical simulation. The test results show that the surface shear stress measured by the oil film interference method is close to the CFD simulation without roughness plate. After adding the rough element, the transition occurs in advance, the surface friction stress increases. The oil film interference method combined with the measurement of surface shear stress with column transfer ribbon that can precisely control the size of the roughness elements can further improve the accuracy, reliability and operability of the simulation of the boundary layer transition in the wind tunnel test model.