基于数值的鲫鱼游泳能力影响参数分析

Analysis of Parameters Influencing Swimming Ability of Crucian Carp Based on Numerical Simulation

鱼类游泳行为机理及游泳能力的影响因素是目前鱼类仿生学研究的热点问题。本文选取鲹科游动模式(carangiform)的典型—鲫鱼(crucian carp)作为研究对象,采用数值模拟的方法,利用动网格技术结合用户自定义函数(UDF),围绕运动参数、鱼体体型及游泳环境(壁面边界),以仿生鲫鱼到达动态稳定的巡游速度这一过程衡量鲫鱼游泳能力,对鲫鱼游泳能力的影响开展研究。结果表明:当摆动频率在0.07~5.50 Hz之间,摆幅系数在0.03~0.06之间,随着鱼体摆动频率和摆动幅度的增大,仿生鲫鱼获得动态稳定巡游速度的时间逐渐缩短,且巡航游速相应增加。将不同厚长比、体长的鲫鱼经过量化处理后进行数值计算,研究结果表明:以相同的摆幅和摆频向前游动,厚长比与游泳速度呈负相关,当厚长比小于0.166,仿生鲫鱼可获得更快的游泳速度;体长方面,将仿生鱼的体长设置为L,仿生稚鱼可更快速地到达巡游阶段,但到达动态稳定的巡航游速较低,约为0.6L s^(–1),仿生幼鱼在加速阶段速度较快,巡游阶段与仿生成鱼的动态稳定巡航游速基本一致,约为1L s^(–1);鱼体在壁面附近游动所产生的壁面效应会导致游泳速度降低,且双侧壁面对仿生鲫鱼游泳速度的影响较单侧壁面更为显著,当鱼体距单侧壁面0.5L,距双侧壁面0.8L时将不受壁面的影响。本文的研究结果可为鱼类仿生学研究提供有益参考。

The mechanisms of fish swimming behavior and the factors influencing swimming ability are pivotal in current research on fish bionomics.The Crucian carp,a typical Carangiform swimmer,is selected as the subject of this study.A numerical simulation method,dynamic grid technology,and User-Defined Functions(UDF)are employed to investigate the effects of motion parameters,fish body size,and swimming environment(wall boundary)on the swimming ability of Crucian carp.This study measures the swimming ability by the time it takes for the bionic carp to achieve a dynamic and stable cruising speed.The findings indicate that when the fluctuation frequency ranges from 0.07 to 5.50,and the amplitude factor is between 0.03 and 0.06,an increase in frequency and amplitude results in a reduction in the time required for the bionic carp to reach a dynamic stable cruising velocity,which also increases the cruising velocity.Dimensionless numerical calculations are performed on Crucian carp with varying thickness-to-length ratios and body lengths.It is determined that body size is inversely proportional to swimming velocity when swimming forward with consistent swing amplitude and frequency.A higher cruising velocity is achieved when the thickness-to-length ratio is less than 0.166.Regarding body length L,juvenile carp can reach the cruising stage more rapidly but exhibit a lower cruising velocity of about 0.6L s^(-1).The speed of the bionic young fish is more pronounced during the acceleration stage,and the cruising stage mirrors the dynamic stable cruising velocity of the bionic adult fish,which is approximately 1L s^(-1).The presence of walls near which the fish swim can diminish the swimming velocity.The impact of bilateral walls on the swimming velocity of bionic carp is more substantial than that of unilateral walls;when the fish body is 0.5L from a unilateral wall and 0.8L from bilateral walls,it is not affected by the wall.These results can provide a valuable reference for research in fish bionomics.