Flow/pressure characteristics for flow over two tandem swimming fish

Fish are good examples of pressure sensing animals. In this paper, flow over two tandem swimming fish is simulated using an immersed-boundary method and the power spectra of pressure sensing are analyzed. The tandem arrangement is an appropriate model for a predator–prey pair as well as for fish cruising in a school. It creates a situation where a low-frequency series of vortices impinging on a downstream object generate acoustic signals with wavelengths comparable to the characteristic length of the flow. As a result of that interaction, the vortex street in the wake shows different patterns, due to different distances between the two fish and different motion frequencies. This analysis is expected to provide some insight of the mechanisms of how pressure sensors inside a fish work together to sense the motions of other fish.