鱼的运动:柔性类箔鳍的动力学与流体力学研究
New experimental kinematic and hydrodynamicdata are presented for pectoral fin function in bluegillsunfish. The highly flexible sunfish pectoral fin moves in acomplex manner with two leading edges, a spanwise waveof bending, and substantial changes in area through the finbeat cycle. Data from scanning particle image velocimetry(PIV) and time-resolved stereo PIV show that the pectoralfin generates thrust throughout the fin beat cycle, and thatthere is no time of net drag. Continuous thrust production isdue to fin flexibility which enables some part of the fin togenerate thrust at all times and to smooth out oscillationsthat might arise at the transition from outstroke to instrokeduring the movement cycle. Computational fluid dynamicanalyses of sunfish pectoral fin function corroborate thisconclusion. Future research on fish fin function will benefitconsiderably from close integration with studies of roboticmodel fins.