Experimental research on influence of wave environment on high-speed water entry load and trajectory characteristics

波面环境对高速入水载荷及弹道特性影响试验研究

¹ School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
² Beijing Electro-Mechanical Engineering Institute, Beijing 100074, China

Received: 7 February 2021

Abstract

Wave environment is a common fact happened when objects enter water under real conditions, which changes the morphology of the free interface when entering water. However, the influence of wave environment on the flow when entering water and on the evolution of object motion parameters after entering water is not clear. In this research, a rocking plate wave maker is used to generate a wave environment in the test pool, and a truncated cone rotating body equipped with an internal test system is used as the test model. The compressed air cannon is used to provide launch power, and the launch control system uniformly controls the start timing process of the wave maker and the launcher. The wave maker and the launcher will control the relative position of the object's entry point and the wave surface in collaboration. Various condition tests were carried out, including enter in static water, different wave surface positions and different wave heights. Quantitative trajectory parameters including the acceleration, and attitude angle of the model in the water-entry process were obtained, and the evolution of the flow field was photographed. The experimental results show that under high-speed conditions, the influence of waves on the water-entry process is mainly reflected in the change of the water entry angle relative to the water surface at the water-entry moment. The wave surface encountering negative inclination can effectively reduce the impact load of water entry, but it is more likely to induce the extreme situation such as "jumping".

摘要

波面环境是真实条件下物体入水所遇到的普遍情形，其改变了入水点自由界面的形貌，对入水过程中流动及入水后物体运动参数演变的影响尚不明确。在试验水池中采用摇板式造波机生成波面环境，以搭载内测系统的截锥头回转体外形为试验模型，利用压缩空气炮提供发射动力，发控系统统一控制造波机与发射炮的启动时序，二者协同以控制模型入水点与波面的相对位置，开展了平静水面、遭遇波面不同位置和不同波高的波浪情形下的入水试验，获得了模型入水过程加速度和姿态角度等定量的弹道参数，拍摄了入水过程的流场演变历程。试验结果表明：高速条件下，波面对入水过程的影响主要体现在其改变了模型入水时刻相对于水面的入水角度，遭遇负倾角情形的波面可降低入水冲击载荷，但更易诱导出现"跳弹"等极端情形。