On the unsteady Kutta condition for the separated fluid flow from a body

Abstract

We consider a vortex shedding model to describe the unsteady separated flow from a body. Both the separated flow and body are regarded as vortex sheets. The solution and unsteady Kutta condition of the model were presented in several different forms. We clarify ambiguities in the solutions and Kutta conditions of the model. We show that the edge circulations between the different approaches are essentially the same, thereby yielding the same vorticity field. We also identify the unsteady Kutta conditions for the solutions of the model. In the analytic solutions, the Kutta condition is the continuity of the sheet strength at the body edges, whereas in the blob-regularized model, the Kutta condition is set to zero of the sheet strength.