Unsteady propulsion and the acoustic signature of undulatory swimmers in and out of ground effect

Propulsive performance and acoustic emission of undulatory swimmers are investigated using an integrated unsteady potential flow and acoustic boundary element solver. Anguilliform and carangiform swimming gaits are modeled by a deforming NACA 0012 airfoil section. The effect of a ground plane on undulatory swimming and associated noise generation is examined as a function of reduced frequency and above plane altitude with the method of images. Ground effect becomes pronounced when swimming within half of a chord length from the ground plane, where the thrust, power, propulsive efficiency, and peak acoustic pressure all increase for both gaits.