二维平板水漂运动数值模拟

探索平板水漂运动的流体力学现象机理对飞行器着水问题的研究有重要的参考价值。基于有限体积法和k-ε RNG湍流模型求解非定常雷诺平均Navier-Stokes（URANS）方程，采用流体体积分数（VOF）模型与速度入口造波法构造数值波浪水池，并结合整体动网格方法，完成二维平板在静水面与波浪水面的水漂运动数值模拟。在与试验值和理论值对比的基础上，讨论初始姿态角、投掷角度与投掷速度对水漂运动的影响。进一步研究不同波浪参数和波浪位置对平板水漂的影响，并从能量角度展开分析。结果表明：20°姿态角平板能以最小的投掷速度实现水漂运动；运动中平板能量的相对损失率受初始投掷速度的影响较小，主要受投掷角和姿态角作用，随投掷角或姿态角的增加而增大。波浪情况下，在上行波位置触水的平板能够获得更大的接触面积，而更长的触水时间发生在波谷处；因此，这两个位置触水的平板在水漂运动过程中的相对能量损失大，其数值变化比波峰位置大5%左右；在上行波位置触水时，平板的速度衰减与相对能量损失随着波高的增加而增大，而波峰位置则有相反的变化趋势。

Numerical simulation of two-dimensional plate skipping

Exploration of the hydrodynamics and mechanism of plate skipping is of significant reference value for the research on aircraft landing problem. Based on the finite volume method and k-ε RNG turbulence model, the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations are solved and a numerical tank is constructed by the velocity-inlet boundary wave maker combined with the Volume of Fluid (VOF) model. Coupled with the global dynamic mesh method, the numerical simulation of two-dimensional plate skipping on both calm and wavy water is carried out. Based on the comparison with experimental and theoretical values, the effects of the initial attitude angle, throwing angle and throwing speed on plate skipping are discussed. Furthermore, the influence of different wave parameters and wave positions is studied and analyzed from the perspective of energy conservation. It is shown that the plate with 20° attitude angle can achieve stone skipping at the minimum throwing speed, and the relative energy loss of the plate is less affected by the initial throwing speed, but mainly affected by the throwing angle and attitude angle, and rises with the increase of the throwing angle or attitude angle. In the case of waves, the plate touching the water at the balance position (up speed) can obtain larger contact area, while the longer contact time occurs at the trough. Therefore, the relative energy loss of the plate contacting the water at these two positions is serious, and the numerical change is about 5% larger than that at the peak position; in the case of touching the water at the balance position (up speed), a rise of the attenuation of velocity and energy loss appears with the increase of wave height, contrary to that at the crest position.