Vortex design problem

In this investigation we propose a computational approach for solution of optimal control problems for vortex systems with compactly supported vorticity. The problem is formulated as PDE–constrained optimization in which the solutions are found using a gradient–based descent method. Recognizing such Euler flows as free– boundary problems, the proposed approach relies on shape differentiation combined with adjoint analysis to determine cost functional gradients. In explicit tracking of interfaces (vortex boundaries) this method offers an alternative to grid–based techniques, such as the level–set methods, and represents a natural optimization formulation for vortex problems computed using the contour dynamics technique. We develop and validate this approach using the design of 2D equilibrium Euler flows with finite–area vortices as a model problem. It is also discussed how the proposed methodology can be applied to Euler flows featuring other vorticity distributions, such as vortex sheets, and to time–dependent phenomena.