斑马鱼C型起动中动力学特性的活体实验研究

提出了一种从鱼类自主游动的运动学实验数据出发推算其动力学特性的实验研究方法。该方法基于变形体动力学方程,不仅可以计算出变形鱼体的整体转动角速度以完善其运动学数据,还可以计算出作用在自主游动的鱼体上的流体合力和流体合力矩,进而分析鱼体的力能学特征。本文运用此方法研究了斑马鱼的两种典型C型起动,对比分析了它们的运动学及力能学特征。结果表明,在相仿的C型弯曲变形下,逃逸型C型起动与非逃逸型C型起动相比,前者推力较大,导致其在前进方向上的质心速率较大;前者侧向力较大,导致其转弯半径较小;前者转矩较大,但因在起动中后期的S型摆动产生了反向转矩,最终导致转动角度小于后者。通过对两种典型C型起动的实验研究发现,斑马鱼会因不同的运动需求而表现出不同的机动性能。

Living Body Experimental Study of Dynamic Characteristics of Zebrafish C-Start Swimming

An experimental method is proposed in this paper to reckon the dynamic characteristics of fish in self-propelled swimming motion via the kinematic data measured from high-speed photography. Based on dynamics equations of deformable body, this method can be used not only to calculate the overall rotation angular velocity for deformable fish to improve its kinematic data, but also to calculate the fluid force and fluid moments acting on fish in self-propelled swimming motion. Based on above data, the mechanical characteristics of living fish can be further analyzed. Using this method, two typical C-starts of a zebrafish were experimentally studied, its kinematic and dynamic characteristics were compared. Results show that in similar C-type bending deformation, comparing C-type start in escape motion with C-type start in non-escape motion, the former thrust is larger than the latter, resulting in a greater speed of its mass center in forward direction; the former lateral force is larger than the latter, resulting in a smaller turning radius; and the former torque is larger than the latter, resulting in a smaller turning angle due to the reverse torque produced by S-type swing in the late stage of start. The present experimental study of zebrafish two typical C-starts shows that it will exhibit different manoeuvres due to the different movement requirements.