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d'Alembert's paradox is the contradictory observation that for incompressibleand inviscid (potential) fluid flow, there is no drag force experienced by abody moving with constant velocity relative to the fluid. This paradox can bestraightforwardly resolved by considering Navier's slip boundary condition.Potential flow around a cylinder then solves the Navier--Stokes equations usingfriction parameter $\beta=-2\nu$. This negative friction parameter can beinterpreted physically as the fluid being accelerated by the cylinder wall.This explains the lack of drag.  In this paper, we introduce the Navier slip boundary condition and show thatchoosing the friction parameter positive resolves d'Alembert's paradox. We thenfurther examine the effect of the friction parameter $\beta$ on the dragcoefficient. In particular, we show that for large $\beta$ the drag coefficientcorresponds well with experimental values. Moreover, we provide numericalevidence that the Newton continuation method (moving from small to largeReynold's numbers) requires fewer iterations to succeed. Thus the slip boundarycondition is advantageous also from a computational perspective.

Resolution of d'Alembert's paradox using slip boundary conditions: The effect of the friction parameter on the drag coefficient