超空泡航行体转弯运动多相流场特性

为研究超空泡航行体转弯运动过程中多相流特性的变化规律,基于有限体积法和VOF多相流模型求解RANS方程,并结合动网格技术,对超空泡航行体转弯运动过程进行了非定常数值模拟研究.通过将数值模拟结果与基于Logvinovich独立膨胀原理的计算结果进行对比,验证了数值模拟方法的有效性.利用数值模拟方法分析了航行体模型的转动中心对航行体转弯运动过程中空泡形态演化过程的影响,并且研究了转弯运动的轨迹半径对航行体流体动力的影响.结果表明:采用动态网格的数值模拟方法可以更好地对超空泡航行体转弯运动的空泡形态进行仿真,航行体的转动中心对航行体的转弯半径内侧还是外侧表面先出现沾湿区域有重要影响;航行体的流域环境在重力和惯性力的共同作用下使得超空泡尾部形态呈倾斜的双涡管分布;转弯运动过程中,航行体表面刚出现沾湿区域的时候,航行体流体动力会出现一个小幅度波动,随着沾湿区面积的增加,流体动力逐渐趋于平稳,转弯运动的轨迹半径对航行体流体动力有重要影响,转弯半径越小,影响越大.

Multiphase flow characteristics of supercavitating vehicle in the tuning motion

To investigate the change rule of multiphase flow characteristics in the turning motion of supercavitation vehicle, the RANS equation is solved based on the finite volume method and VOF multiphase flow model. Combined with the dynamic mesh technology, an unsteady numerical simulation study is conducted. By comparing the numerical simulation results with the calculation results based on Logvinovich independence principle, the effectiveness of the numerical simulation method is validated. The influence of rotate center of vehicle on the cavity shape and that of turning radiuses on the hydrodynamic characteristics of vehicle for the turning motion are analyzed by the numerical simulation. The results show that the numerical simulation method of dynamic mesh can simulate the cavitary shape of the turning motion of the supercavitation vehicle better. The rotation center of the vehicle has an important influence on the wetting area on the inner or outer surface of the turning radius of the vehicle. The valley environment of the vehicle makes the shape of the super cavity tail appear inclined double vortex tubes under the combined action of gravity and inertial force. During the turning motion, when the wetting area appears on the surface of the vehicle, the fluid dynamics of the vehicle will have a small amplitude fluctuation. The fluid dynamics tends to be stable with the wetting area increasing. And the trajectory radius of the turning motion has a great influence on the fluid dynamics of the vehicle. The smaller the turning radius is, the greater the influence is.