Simulations are carried out for different amplitudes and intermittent distances to study the two-dimensional vortex wakes behind a pair of flapping plates. In particular, solutions are compared using a mean lift to drag ratio for flappers at the intermittent distance of 1cm and 10cm. The simulation results clearly show that symmetric flappers in certain range of close proximity are able to provide effective propulsion.

vortex separation, flapping plates, flow separation.