We study the flow past a rough sphere considering the rugosity as a parameter and its effect on the drag coefficient. The numerical implementation is carried out via a novel approach using Galerkin’s method combined with an asymptotic expansion for the stream function. The amplitude of the spatial fluctuation is used as the perturbation parameter. The numerical results for the size of the vortex ring and streamlines in the smooth case are compared with experimental data found in the literature. In addition, when the surface is rough, we compare the numerical results with the smooth case and the implications of the rugosity in the separation point and other features of the flow are discussed.

我们将粗糙度作为参数及其对阻力系数的影响，研究通过粗糙球体的流动。通过使用Galerkin方法结合流函数的渐近展开的新颖方法来执行数值实现。将空间波动的幅度用作摄动参数。将光滑情况下涡流环和流线的尺寸的数值结果与文献中的实验数据进行了比较。此外，当表面粗糙时，我们将数值结果与光滑情况进行比较，并讨论了分离点的皱纹和流动的其他特征的含义。