中文摘要：

为研究线性剪切来流对方柱绕流特性的影响,将对流出口边界条件引入特征线算子分裂有限元法中,建立了线性剪切来流的方柱绕流数值模型,并采用均匀来流的方柱绕流模拟结果验证了该模型计算方柱绕流问题的可靠性。数值模拟结果表明,剪切参数k对方柱绕流尾部形成的两排涡影响明显,涡脱落在k较大时被抑制,在k≥0.4时涡量最终形成一个类似三角形的区域;驻点随k的增加逐渐向高速侧分离点移动,在k≥0.3时驻点的位置不再发生变化;平均阻力系数在0.2≤k≤0.25时发生较大变化,平均升力系数在k≥0.2时为负。

英文摘要：

In order to investigate the effects of linear shear flow on characteristics of flow past a square cylinder, a numerical model for shear flow past a square cylinder was established by introducing the convective outflow boundary condition into the characteristic-based operator-splitting finite element method. The reliability of the numerical model was verified through simulation of the uniform flow past a square cylinder. The numerical results show that the shear parameter k has a significant effect on the two rows of vortices in the wake of flow past the square cylinder, and a larger k value inhibits the vortex shedding from the cylinder. When k ≥0. 4 ,the formation region of vortices behind the cylinder becomes a triangular zone. As the value of k increases,the stagnation point shifts towards the lateral separation point. When k ≥ 0. 3, the location of the stagnation point remains unchanged. The significant change in the mean drag coefficient occurs in the range 0. 2 ≤k ≤0. 25. When k ≥0. 2 ,the mean lift coefficient is negative.