【作者】 陈科； 尤云祥； 胡天群； 朱敏慧； 重劲松； 王小青；

【Author】 CHEN Ke,YOU Yun-xiang,HU Tian-qun State Key Laboratory of Ocean Engineering,Shanghai Jiaotong University,Shanghai 200030,China, ZHU Min-hui CHONG Jin-song WANG Xiao-qing State Key Laboratory of Microwave Imaging Technology,Institute of Electronics,Chinese Academy of Sciences, Beijing 100080,China

【机构】 上海交通大学海洋工程国家重点实验室； 中国科学院电子学研究所微波成像技术国家重点实验室；

【摘要】 采用拖曳球体与移动喷管相结合的方法,模拟了拖曳体阻力动量J_D与移动射流动量J在分层流体中的相互作用,研究了这种组合式动量尾迹的演化特性。研究表明,当J_D/J>C_D时,组合式动量尾迹的演化特性主要受阻力动量控制,形成正卡门型准二维偶极子涡街结构,其中C_D为拖曳球体的阻力系数。当J_D/J<C_D,组合式动量尾迹主要受射流动量控制,射流雷诺数Re_j与射流傅汝德数Fr_j的组合条件对其演化特性影响较大:在(Re_j,Fr_j)满足临界条件的前提下,组合动量尾迹会形成反卡门型准二维偶极子涡街结构,并且其演化规律与Fr_j关系密切,成幂指数的关系;若不满足临界条件,则不会产生大尺度的相干结构。更多还原

【Abstract】 A towed sphere and a moving nozzle jet were used respectively to simulate a drag momentum J_D and jet momentum J to generate a joint-momentum wake in a density stratified fluid. The evolution characteristics of the joint-momentum wakes were investigated through series experiments.It is shown that for J_D/J<C_D,the evolution characteristics for the joint-momentum wakes are mainly attributed to the drag momentum and the far wake becomes quasi two-dimensional(2D) in the form of a Karman-like dipolar vortex street,where C_D is the Drag coefficient of the sphere.For J_D/J<C_D,the evolution characteristics for the joint-momentum wakes are mainly attributed to the jet momentum which are mainly dependent of(Re_j,Fr_j),the combinatin of jet Reynolds and Froude number condition.If(Re_j,Fr_j) contents the critical condition,the far wake becomes quasi 2D in the form of an anti-Karman-like dipolar vortex street and index laws are deduced on its temporal and spatial characteristics versus Fr_j.Otherwise,only small-scale structures exist in the wakes attributed to jet momentum.更多还原