均匀湍流场下矩形断面流场及气动参数数值模拟

Simulation of rectangular section's flow field and aerodynamic parameters in homogeneous turbulence

采用大涡模拟方法数值模拟了两种矩形断面(B/H=1,B/H=2)在不同湍流来流下的流场及气动参数,采用谐波合成方法生成与目标谱一致的脉动入口风速。数值计算结果表明来流湍流对断面的流场及气动参数有较明显的影响,通过与均匀来流的计算结果作对比可以看出,湍流导致断面的阻力系数减小明显,其主要原因为背压区负压系数的增加,与实验的结果较一致;从流场分布看湍流主要影响断面尾流涡的形成,这种影响会影响尾流涡的形成。

Large-eddy simulation is used to predict the flow past rectangular sections （B/H= 1, B/H=2） in different turbulent flow fields. While stochastic method is applied to generate homogeneous turbulence with specified power and cross spectra for the velocity inlet. Compared with the results about the smooth flow and different turbulent flow, it can be found that turbulence will decrease the drag coefficients, which is caused by the reducing of the pressure coefficients in wake, this character is the same with the results of previous experimental studies. Turbulence will also accelerate or depress the formation of wake vortex mainly through the flow field.