半疏水-半亲水球体垂直入水空泡数值仿真研究  

Numerical Investigations on Water-entry Cavity of Half Hydrophobic-half Hydrophilic Sphere

作　　者：孙钊[1] 曹伟[1] 王聪[1] 路中磊 

机构地区：[1]哈尔滨工业大学航天学院,黑龙江哈尔滨150001

出　　处：《兵工学报》2017年第5期968-977,共10页Acta Armamentarii

基　　金：国家自然科学基金项目(11672094);哈尔滨市科技创新人才专项基金项目(2013RFLXJ007)

摘　　要：采用流体体积多相流模型耦合连续表面力模型,对具有非对称表面润湿性的半疏水-半亲水球体垂直入水空泡形态发展过程进行数值仿真,分析了半疏水-半亲水球体垂直入水过程中受到的流体动力。研究结果表明:半疏水-半亲水球体垂直入水后,产生非对称入水空泡及"心"型喷溅,同时球体运动轨迹将偏离原竖直运动轨道,由疏水半球一侧向亲水半球一侧偏斜;入水初期,在球体表面形成液体薄层运动,在疏水半球一侧,液体薄层与球体表面分离,导致空气进入形成敞开空泡;在亲水半球体一侧,液体薄层沿球体表面向上运动最终在球体顶点汇聚;液体薄层汇聚后形成楔形流,楔形流在球体顶点与球体表面分离,继续向疏水半球一侧产生的入水空泡壁面运动并撞击,形成"心"型喷溅。The water entry of a solid sphere impacting on a liquid surface has challenged researchers for centuries and remains of interest to the researchers today. A simulation study of the water entry cavity of half hydrophobic-half hydrophilic sphere is performed. Particular attention is given to the simulation method based on solving the Navier-Stokes equations coupled with VOF model and CSF model. The numerical results are in agreement with the experimental results, thus validating the suitability of the numerical approach to simulate the water entry of sphere under different wetting conditions. Based on this meth- od, the development of cavity created by the half hydrophilic-half hydrophobic sphere is investigated. Re- sults show that the water entry of half hydrophobic-half hydrophilic sphere creates an asymmetric cavity and ＂cardioid＂ splash, which causes the sphere to travel laterally from the hydrophobic side to the hydro- philic side. Further investigations show that the fluid film presents during initial stage of impact, and on the half hydrophobic sphere, the fluid film detaches from the sphere to lead to cavity formation; on the half hydrophilie sphere, the fluid film moves up on the sphere surface and gathers at the vertex of the sphere, forming a wedge flow. The wedge flow moves and finally impacts on the opposite side of the cavity so as to cause ＂cardioid＂ splash. In addition, the total hydrodynamic force coefficient is investigated as a result of the forces acting on the sphere during water entry dictated by the cavity formation.

关 键 词：流体力学 多相流 半疏水-半亲水球体 垂直入水 表面润湿性 数值仿真 空泡 

分 类 号：TV131.22[水利工程—水力学及河流动力学]