Impact of a vortex dipole with a semi-infinite rigid plate

Abstract

The physics of a two-dimensional vortex dipole impinging on the tip of a semi-infinite rigid plate is numerically examined. The dipole trajectory is initially orthogonal to the plate and aligned with its tip. The impact behavior is examined for three dipole Reynolds numbers. As the dipole approaches, vorticity is induced along the plate, as in the case of a dipole approaching a full wall, and is additionally shed from the tip. Upon impact, the dipole effectively splits, with half of it interacting with the vorticity induced on the plate and the other half with the vorticity shed from the tip. Each half of the original dipole forms a new secondary vortex pair whose behavior depends upon the Reynolds number of the original dipole. Contingent upon the rate of momentum diffusion, these secondary (and tertiary) vortex pairs may return and impact the plate again. Herein, we detail the interaction of the dipole impact at various Reynolds numbers, with a focus on the vortex dynamics and the distributed load imposed on the rigid plate by the fluid.