Kinematic Modeling and Dynamic Analysis of the Long-Based Undulation Fin of Gymnarchus Niloticus

Abstract

Within median and/or paired fin (MPF) propulsion, many fish routinely use the long-based undulatory fins as the sole means of locomotion In this paper, the long-based undulatory fin of an Amiiform fish“G niloticus”was investigated We brought forward a simplified physical model and a kinematic model to simulate the undulations of the long-based dorsal fin Further, the equilibrium equations of the undulatory fin were obtained by applying the membrane theory of thin shells in which the geometrical non-linearity of the structure is taken into account Last, we apply the derived kinematic model and equilibrium equations of the undulatory fin to analyze the thrust and propulsive efficiency varying with the aspect ratio of the fin and the maximum swing amplitude.