Larger wavelengths suit hydrodynamics of carangiform swimmers

The wavelength of undulatory kinematics of fish is an important parameter to determine their hydrodynamic performance. This study focuses on numerical examination of this feature by reconstructing the real physiological model and kinematics of steadily swimming Jack Fish. We perform three-dimensional numerical simulations for flows over these models composed of the trunk, and dorsal, anal, and caudal fins. Moreover, we prescribe the carangiform-like motion for its undulation for a range of wavelengths. Undulation with larger wavelengths improves the hydrodynamic performance of the carangiform swimmer in terms of better thrust production by the caudal fin, lower drag production on the trunk, and reduced power consumption by the trunk. This coincides with the formation of stronger posterior body vortices and leading-edge vortices with more circulation on the caudal fin. The real kinematics of Jack Fish surpasses the performance of those with prescribed motion owing to the flexibility of the caudal fin.

Automated summary

The study examines the impact of fish undulatory motion wavelength on hydrodynamic performance, indicating that larger wavelengths can improve swimming efficiency. By performing numerical simulations on the Jack Fish model, it was found that longer wavelengths lead to better thrust production, reduced drag, and lower energy consumption.