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Drag and Moment in Viscous Potential Flow

D. D. Joseph, T. Y. Liao and H. H. Hu

Department of Aerospace Engineering and Mechanics, University of Minnesota, Minneapolis, MN 55455 (USA)

(May 1992)


We consider solutions of the Navier-Stokes equations in which the velocity is given by the gradient of a potential. We show that the drag on bodies and bubbles is the same in viscous and inviscid potential flow. The lift on two-dimensional bodies is given by the usual Kutta condition but the moment about the origin of the stresses acting on the body is given by where is the viscosity, is the circulation and is the usual moment for an inviscid fluid.