自由液面下增阻器水动力特性的数值仿真

Numerical Simulation of Hydrodynamic Characteristics of a Drag Device with Free-water Surface Flow

水力增阻器是一个利用水的阻力来实现高速运动物体减速的装置。采用RANS方程和RNG湍流模型对增阻器特性进行了数值仿真计算,能得出了流场的自由液面变化情况、增阻器表面压力分布以及阻力系数随浸深和来流速度的变化规律等,从中缩短了增阻器阻力计算周期并节约了阻力试验成本。计算结果表明:增阻器压力主要集中在增阻器背面与流体接触面上,最大压力出现在增阻器拐角处下端;增阻器阻力系数受来流速度影响不大,但随着浸水深度的增加呈现总体减小的趋势。可为增阻器的结构设计以及阻力预报提供重要参考依据。

The hydrodynamic drag device can utilize the water resistance to oppose or retard the motion of mechanism. The numerical simulation of hydrodynamic characteristics in different submergence and at different initial velocity can be carried out by using Reynolds Averaged Navier -Stokes （RANS） Equations and the Renormalization Group （RNG） turbulence model. The variety of the free surface and surface pressure distribution of the drag device are investigated and the trend of resistance coefficient with variety of submergence and initial velocity which can shorten computing period and cut down experiment cost is also described. The results indicate that, pressure mainly concentrates on the contact surface between the back side of the drag device and the fluid surface, and the greatest pressure is present to the bottom corner, and the resistance coefficient is affected less by the initial velocity and it generally decreases as the water gets deeper. The conclusion could be an important reference for the structural design of the drag device and prediction of hydrodynamic characteristics.