圆柱跨声速绕流中的激波/湍流相互作用大涡模拟研究

Large eddy simulation of shock-wave/turbulence interaction in the transonic flow over a circular cylinder

采用大涡模拟方法研究了圆柱跨声速绕流中的激波/湍流相互作用问题,来流马赫数M∞取为0.75,基于圆柱直径D的雷诺数为2×105。计算结果表明,圆柱分离点处出现一道斜激波,并且以与涡脱泻Strouhal数一致的特征频率向上游传播。激波运动导致流场中出现反对称的流动模态,剪切层中压力信号的功率谱曲线中存在0.4、-1和-5次方的斜率关系,剪切层中的剪切应力角约为0°,脉动速度以流向脉动速度为主,并且沿剪切层的大尺度结构组织性减小。

Shock-wave/turbulence interaction over a circular cylinder is investigated using large eddy simulation for the free-stream Mach number 0.75 and Reynolds number 2×105 based on the diameter of the cylinder.An oblique shock wave occurs at the separation point and moves upstream with the same Strouhal number as that of vortex shedding.Moreover,shock-wave motion can induce the antisymmetric flow mode.The pressure probe inside the shear layer region is monitored,and three slopes are found in the power spectral density curve,i.e.,0.4,-1 and-5.A strong orientation of shear stress inside the shear layer region is around 0°,which indicates that velocity fluctuations are dominated by the streamwise component.Moreover,there is an indication of the loss in organization of the large-scale turbulent structures along the shear layer.