高速平板着水数值模拟

探索和揭示物体入水冲击的流体力学现象与机理对飞行器水上迫降问题的研究有重要的参考价值。对高速平板着水涉及到的复杂物理问题展开数值模拟,采用有限体积法求解非定常雷诺平均Navier-Stokes(URANS)方程和标准k-ε湍流模型,流体体积(VOF)模型捕捉水气交界面,整体动网格技术处理平板与水面的相对运动。在二维楔形体入水冲击的算例验证基础上,详细研究平板高速着水引起流体喷溅、射流、空气垫等现象和平板底面压力变化历程,结果表明:空气垫现象明显,俯仰角4°平板下表面出现规律的空气泡,10°时则不存在;平板下表面的水体沿壁面运动,当俯仰角为10°时,壁面水体的运动速度显著增加;在大俯仰角的情况下明显出现负压区。

Numerical simulation of high speed plate ditching

To have a deeper understanding of aircraft ditching,it is crucial to explore the hydrodynamics and mechanism of impact of water-entry objects.This paper numerically investigates the complex physical problems of high speed plate ditc-hing using the finite volume method coupled with the Volume of Fluid (VOF)model.The Unsteady Reynolds-Averaged Navi-er-Stokes (URANS)equations and the Standard k-ε turbulence model are solved by the finite volume method.The VOF mod-el is applied to capture the air-water interface.The relative motion between the plate and water is handled by the global dy-namic mesh method.The high speed ditching of a 2D wedge-shaped body is studied,including the pressure distributions on lower surface of the plate and free surface deformations such as splash formation,movement and air cushion effects.The re-sults show that there is obvious air cushion in the plate,with occurrence of regular air bubbles under the plate at 4°pitching angle,while no occurrence of air bubbles at 10° pitching angle.The water under the plate moves along the bottom of the plate,and the water speed increases dramatically at 10°pitching angle.The negative pressure zone appears significantly at large pitching angle.