旋转圆柱绕流的流场特性

在亚临界区Re=1.4×105条件下，基于大涡模拟（LES）方法对均匀来流作用下的旋转圆柱绕流进行了数值模拟。通过与非旋转时的实验和计算结果比较，验证了文中计算的准确性。在此基础上，对不同转速条件下（0≤α≤2，α为圆周线速度与自由来流速度的比值）的圆柱绕流进行了数值研究。结果表明，圆柱旋转可以有效地抑制其旋涡脱落，随着转速的增加，可大幅提高其升阻比，主要表现为阻力系数减小而升力系数线性增大。当α=2时，阻力系数和升力系数在经过短暂过渡期后达到稳定。

Flow field characteristics of flow past a rotating cylinder

Under the sub-critical condition with Re=1.4×105, flow past a rotating cylinder with uniform inflow is simulated numerically with Large Eddy Simulation (LES). The results are verified accurately through the comparison of the corresponding experimental and simulated results of the non-rotating case. Furthermore, flow past a rotating cylinder with different spin ratios (0≤α≤2, αis the ratio of the cylindrical circumferential speed to the free-stream speed). The numerical results show that the rotation of the cylinder can suppress vortex shedding effectively, and with the increase of spinning ratio, the mean drag coefficient of cylinder decreases while the lift coefficient increases. The amplitude of mean drag and lift coefficients become steady through a short transitional period forα=2.