The flow by the rotational oscillation of the flat plate.

It is interesting to examine the flow around a body that is impulsively started to oscillate from rest. We analyze the flow around a float plate acting in a rotational oscillation about one end of the plate in a stationary fluid, using the discrete vortex model with the comformal mapping method. The numerical conditions are determined by comparing the flow with the results of flow visualization already reported. Then, numerical calculations are performed for several angles of amplitude under the above conditions. Vortex patterns, velocity profiled and unsteady forces are obtained. As a result, a pair of vortex clusters are generated above and below the plate for each angle of amplitude. The fluid flows in the rear of the plate by this oscillation. The mean drag coefficient is constant, having nothing to do with the angle of amplitude.