Boundary Condition Influence on the Flow Around a Circular Cylinder

Two-dimensional simulations of the flow around a circular cylinder, performed at several values of the Reynolds number, revealed that when a constant velocity is assigned at the outer boundary, accurate solutions are obtained only for large distances of the boundary from the body. On the other hand, at a reasonable distance from the cylinder, radiative boundary conditions produce results which compare well with the experimental observations, also if the external boundary is quite close to the cylinder.