Visualization of Steady Flows Induced by a Circular Cylinder Performing a Rotatory Oscillation about an Eccentric Axis

The steady streaming induced by a circular cylinder performing a rotatory oscillation about an eccentric axis in a fluid which is otherwise at rest is investigated by means of a flow visualization method. The solution of glycerine in water is used as the working fluid. The aluminum dust method is used for flow visualization. It is found that when δ<0.2 the flow consists of two layers, the inner layer and the outer layer, and that when δ>0.2 the inner layer spreads over the whole flow field, where δ is the non-dimensional thickness of the Stokes layer. It is also found that when δ<0.1 a jet-like flow is produced in the outer layer.