考虑表面形貌效应的球体入水动力学特性研究  

Water entry dynamics of spheres considering the surface topography effect

作　　者：王兆长 刘小君[2] 童宝宏[1] 张国涛 刘焜[2] 焦云龙 WANG ZhaoChang;LIU XiaoJun;TONG BaoHong;ZHANG GuoTao;LIU Kun;JIAO YunLong(College of Mechanical Engineering,Anhui University of Technology Maanshan 243000,China;Institute of Tribology,Hefei University of Technology,Hefei 230000,China;State Key Laboratory of Tribology in Advanced Equipment,Tsinghua University,Beijing 100084,China)

机构地区：[1]安徽工业大学机械工程学院,马鞍山243000 [2]合肥工业大学摩擦学研究所,合肥230000 [3]清华大学高端装备界面科学与技术全国重点实验室,北京100084

出　　处：《中国科学：物理学、力学、天文学》2024年第6期176-188,共13页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:51975005,51975174,52375178);安徽工业大学青年教师科研基金(编号:QZ202308);高端装备界面科学与技术全国重点实验室开放基金(编号:SKLTKF23B04);安徽省自然科学基金(编号:2308085ME158)资助项目。

摘　　要：运动体入水现象广泛存在于自然界和海洋工程等领域,如各种水生生物水上行走、大型船舶海上航行以及鱼雷水下行进等,在运动体表面构筑气腔对实现水下减阻具有重要意义.本文通过控制腐蚀溶液的高度制备了微结构面积占有率不同的球体,分析了微结构面积占有率不同的球体垂直入水多相流动过程和减阻特性,并从能量角度揭示了非对称入水气腔偏转机制.研究结果表明,非对称微结构球体入水过程中由于水平方向动量传递不平衡使其球体轨迹发生横向偏移;当非对称微结构球体入水出现气腔夹带时,表面的无滑移边界条件转变成了气-液界面的自由滑移边界条件,使得流体阻力降低了82.9%-93.4%.本研究通过调控球体的表面形貌产生的非对称气腔为调控水下航行体的运动轨迹提供了一种新的策略.The phenomenon of moving bodies into water widely exists in nature and ocean engineering,such as various aquatic organisms walking on water,large ships sailing on the sea,and torpedoes traveling underwater.It is imperative to construct air cavities on the surface of the moving body to achieve underwater drag reduction.In this study,spheres with different microstructure area occupancies are prepared by controlling the height of the corrosion solution.Afterward,the multiphase flow process and drag reduction characteristics of the obtained spheres with different microstructure area occupancies are analyzed for vertical water entry.In addition,the deflection mechanism of an asymmetric water entry gas cavity from the energy perspective is presented.The findings reveal that the trajectory of the asymmetrically microstructured sphere is shifted laterally due to the momentum transfer imbalance in the horizontal direction during the water entry process;moreover,the no-slip boundary condition on the surface is transformed into a free-slip boundary condition at the gas-liquid interface when air-cavity entrapment takes place in the water entry of the asymmetrically microstructured sphere,which reduces the fluid drag force by 82.9%-93.4%.This study offers a novel approach for regulating the trajectory of an underwater moving body using an asymmetric air cavity generated by modulating the surfacetopography of spheres.

关 键 词：表面形貌效应 入水气腔 流体动力 减阻 

分 类 号：O35[理学—流体力学]