Numerical simulation of flow around a sphere with vortex blobs

Abstract

A vortex model of a blob method (which is one of the vortex methods proposed before) is modified to take into account the viscous effect. The modified method was applied to simulation of a flow around a sphere using the Boundary Element Method. The surface of the sphere was represented by the distributed source panels. The continuous distribution of vorticity over the surface of the sphere was replaced by a number of vortex blobs. All the blobs were allowed to flow at their own convective velocities, and the boundary layer separation was expected to be naturally represented by their convective motion. As a result of this calculation, the boundary layer separation from the surface was reasonably simulated in the initial stage of a starting flow.