鳞鲀倒游机动的机理研究

Study on mechanism of balistid’s backward maneuvering

鳞鲀倒游机动的机理研究可为多方向机动性人造水下航行器设计提供新思路。该文通过数值研究,揭示了鳞鲀倒游机动的推进机理。研究发现,鳞鲀的倒游游动和前游游动相比,推力较小,效率较低,其主要原因是倒游的尾迹涡不像前游沿水平方向脱出,而是与水平面存在一定夹角;倒游还会脱出较强的鱼体涡,且在中鳍前缘尖部脱落小涡。鳞鲀在倒游时,只依靠背鳍或臀鳍波动,就可以轻松地实现下沉或上浮运动;鳞鲀倒游时,若将尾鳍适当收缩,或将扳机展开,均会增加推力,而效率几乎不变。

The study on the mechanism of the balistid’s backward maneuvering can provide new ideas for the design of multi-directional maneuverable underwater vehicles.The mechanism of balistid’s backward maneuvering is revealed in this paper by numerical simulation.It is found that the thrust and propulsive efficiency in balistid’s backward swiming are lower than those in its forward swimming because of a certain angle between the wake vortices and the horizontal plane,the vortices shedding from the trunk and the small vortices shedding from the leading edge of median fins in backward swimming.A balistid can sink or float in backward swimming by only undulating its dorsal fin or anal fin.In addition,if the caudal fin is suitably contracted or the trigger is extended during backward swimming,the thrust will be higher while the propulsive efficiency will be almost unchanged.