Based on a novel method of force analysis,the thrust and drag forces of self-propelled fish are redefined,and the difficulty in distinguish the thrust and drag in fish swimming is overcome.Then,an adaptive ghost-cell immersed boundary method is used to simulate the 2D self-propelled carangiform swimming.Simulation cases are carried out for Reynolds number in the rang of 309≤Re≤14 581（viscous flow） and Re =∞（inviscid flow）.The results show that：（1） The Strouhal number decreases with increasing the Reynolds number. If the Reynolds number tends towards infinite,the Strouhal number approaches 0.25;（2） For all Reynolds number,the main part of the thrust is the pressure component.The viscous part of the drag is larger than the pressure part when Re 3 000,while the relationship will be reversed when Re 3000;（3） The thrust efficiency increases with increasing the Reynolds number and the maximum efficiency is about 70%.The result show that the carangiform swimming rule suit the high Reynolds situation.%通过对推力和阻力进行重新定义，从根本上解决了鱼游研究中推力和阻力无法区分的难题.在此基础上，利用自适应网格下的ghost-cell浸没边界方法，模拟了鱼类以鲹科模式在粘性流体（309≤Re≤14581）和无粘流体 （相当于雷诺数无穷大情形） 中的二维自主游动.结果表明：（1）Strouhal数随雷诺数增大而减小，当雷诺数趋向于无穷时，Strouhal数趋向于0.25；（2）在所有雷诺数情况下，推力主要来源于压力分量；当Re〈3000时，阻力的压力分量小于粘性力分量，而当Re〉3000，二者的关系就会反过来；（3）推进效率随着雷诺数的增大而增大，当雷诺数趋向于无穷大时，推进效率最高可以达到70%，说明鲹科模式适用于较高雷诺数下的游动.
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