鱼类游动的N—S方程数值模拟

通过求解二维守恒型非定常流动N-S方程，对鱼类运动时鱼体周围二维非定常流场进行数值模拟，数值计算空间采用有限体积离散，时间推进格式采用Jameson的双时间法。描述了各状态鱼体模型、计算网格的生成方法和数值计算方法。结合计算结果对鱼类游动时反卡门涡街的形成和鱼体推力的产生机理进行了分析，并对不同斯特哈尔数对推力的影响进行了研究。结果表明：非定常N-S方程数值方法能够正确模拟鱼体运动时的流场和反卡门涡街的形成；产生明显推力的St数的范围是0．23～0．53，而且在0．35处推力达到最大。

N-S Equations Numerical Simulation of Swing of Fish

The two-dimensional field of swimming fish is simulated with numerical method based on the solution of the two-dimensional unsteady Navier-Stokes Equations in which the finite volume method and dual-time stepping method is used. The methods of generating the model of fish and its mesh are also described. With the computation results, the forming mechanism of reverse Karman vortex street and the thrust to fish when it swim are analyzed, and the influence of different St number to thrust is researched as well. It is shown from the result that the numerical method of unsteady Navier-Stokes Equations could simulate the field of swimming fish and the process of forming of reverse Karman vortex street correctly ; the scale of St number which generate obvious thrust is 0. 23 - 0. 53, and the peak value appears at 0. 35.