流体压缩性对气泡RT不稳定性的影响  

THE INFLUENCE OF COMPRESSIBILITY ON RT INSTABILITY OF BUBBLE

作　　者：汪跃鸣 孙远翔[1] 王成[1] Wang Yueming;Sun Yuanxiang;Wang Cheng(State Key Laboratory of Explosion Science and Safety Protection,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]北京理工大学爆炸科学与安全防护全国重点实验室,北京100081

出　　处：《力学学报》2024年第12期3418-3429,共12页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金资助项目(12221002)。

摘　　要：气泡载荷的研究对于设计舰船与海上建筑是必要的,然而存在于流体中的气泡并不稳定,气泡不稳定性现象会改变气泡对周围结构的载荷特性,影响气泡射流的形成.气泡界面的不稳定现象关系到水下战斗部的毁伤能力.在水下爆炸中,爆炸形成的大尺寸高压气泡内部气压最高可达几万大气压,这时,气泡周围的水的压缩效应不可忽略,而传统的气泡界面Rayleigh-Taylor(RT)不稳定性解析理论假设气泡周围的流体是不可压缩的.文章通过理论分析得到气泡周围流体的可压缩性对气泡界面RT不稳定性的影响,建立了考虑压缩性的解析理论.文章得到的结论为:对于水下爆炸气泡,在气泡膨胀时,压缩性略微抑制界面不稳定性;在气泡收缩时,压缩性促进界面不稳定性.并且,考虑压缩性时,RT不稳定性发生指数爆炸性增长的时刻相比于不考虑压缩性时提前.对于低内压气泡,压缩性始终起抑制界面不稳定性的作用.对于微米级气泡,压缩性抑制界面扰动的第一个峰值,但同样使RT不稳定性发生指数爆炸的时刻提前.黏性与表面张力仅抑制微米级气泡界面不稳定性.The study of bubble load is necessary for the design of ships and marine buildings.However,the bubbles in the fluid are not stable.The Rayleigh-Taylor(RT)instability of the bubble will affect the load behavior of the bubble on the surrounding structure.For example,interface RT instability prevents bubble from forming jets with destructive effects.Thus,the instability of the bubble interface affects the damage ability of the underwater warhead.The bubble formed by the detonation products of underwater explosion has high internal pressure and large size.In the underwater explosion,the internal pressure of the bubble can reach tens of thousands of atmospheres.In this case,the compression of the water cannot be ignored.However,in the traditional analytical theory of RT instability for bubble,liquids are assumed to be incompressible.Therefore,an analytical theory of RT instability for bubble containing compressibility is established in this paper.The conclusions of this paper are as follows:For underwater explosion bubble with high internal pressure and large size,compressibility inhibits the interface instability slightly when the bubbles expand.Compressibility promotes interfacial instability when bubble contraction.Moreover,compressibility can bring forward the time when exponential growth of RT instability occurs.In contrast,for low internal pressure bubbles,compressibility simply inhibits RT instability.For micrometer bubble,compressibility reduces the first peak of interfacial disturbance.Similarly,compressibility can bring forward the time when exponential growth of RT instability occurs for micrometer bubble.In addition,the surface tension and viscosity of water can inhibit the interfacial RT instability of micrometer bubble.In contrast,the surface tension and viscosity of water have little effect on the interfacial RT instability of bubble formed by underwater explosions.

关 键 词：气泡 界面不稳定性 RAYLEIGH-TAYLOR不稳定性 可压缩性 球谐函数 

分 类 号：O354[理学—流体力学]