Why do anguilliform swimmers perform undulation with wavelengths shorter than their bodylengths?

Understanding the connection between physiology and kinematics of natural swimmers is great importance to design efficient bio-inspired underwater vehicles. This study looks at high-fidelity three-dimensional numerical simulations for flows over an undulating American eel with prescribed anguilliform kinematics. Particularly, our work focuses on why employ wavelengths shorter than their bodylengths while performing wavy For this purpose, we vary undulatory wavelength a range values generally observed in different aquatic animals Strouhal numbers 0.30 0.40. We observe that swimmer able demonstrate more suitable hydrodynamic performance 0.65 0.80. longer wavelengths, experiences large frictional drag, which deteriorates its performance. The wake topology was dominated by hairpin-like structures, are closely linked underlying physics swimming found nature.