The performance of a new immersed boundary method on simulating underwater locomotion and swimming

We report the benchmark results of a new Immersed Boundary Method (IBM) incorporated into Direct Numerical Simulation (DNS) of a pitching panel, representing fishlike swimming, using foam-extend-3.2. The panel is flat and thin, and it has a triangular (convex) trailing edge, similar to that seen in the caudal fin of some fish. The accuracy of the solver is verified by comparing four cases of bluff body wake simulations with reported experimental and numerical studies. For example, the structure of the mean wake compared well with that obtained using PIV in a companion experiment. The differences in thrust generation and propulsion efficiency of square and convex thin panels are examined to identify the effect of trailing edge shape using proper orthogonal decomposition. The effect of Reynolds number is also evaluated by comparing the wake at Reynolds numbers of 2,000 and 10,000.