Observation and hydrodynamic analysis of fast-start of yellow catfish (Pelteobagrus fulvidraco)

摘要

The kinematics and hydiodynamics of the escape response of yellow catfish (Pelteobagrus fulvidraco) is investigated. It is observed fiorn digital high-speed camera that all the escape lesponse of yellow catfish is a C-type fast-start, which is characterized by the C-shape of the fish body at the end of the first contraction of the lateral musculature Based on the analysis of the mass center movement and the performance of the caudal fih, the fast-start process can be divided into two stages; in stageone the fish body rotates rapidly around its mass center and in stage two the fish begins moving straightly. Theoretically, the Weihs' model is employed to obtain the forces, moments and turning angular accelerations acting on the fish during the escaperesponse. The results are in good agreement with the experimental observation, Furthermore, muscle strain at different locations along the body is calculated At last, the dynamical performance of the escape response is explained.