下凹内孤立波流场与横置细长潜体相互作用特性的实验研究

Experimental study on the flow variation of internal solitary wave and its interaction with a traverse submerged slender body

该文在大型重力式分层流水槽中开展横置细长潜体遭遇下凹内孤立波的流场和作用力特性的实验研究,采用PIV技术测量内孤立波及其与潜体相互作用时的流场变化,同时利用测力传感器测量潜体所受水平与垂向力的变化,分析入射波振幅以及潜体潜深变化对作用力的影响情况。研究表明:内孤立波诱导流场的整体特征表现为,在上下两层流体中形成强烈的水平剪切流,上层流速大于下层流速且方向相反,在波前后分别形成下沉与上升流动;潜体所受水平力主要由内孤立波诱导流场决定,而垂向力则由密度场与流场变化的耦合作用决定;在横置细长体遭遇内孤立波过程中,其后部产生的涡旋结构导致高密度流体团的滞留继而逐渐扩散,它是决定沿内孤立波传播方向横置与平行放置细长潜体时两者垂向作用力差异的重要原因。

In a large-type gravity stratified fluid tank, laboratory experiments are conducted to study the interaction between an internal solitary wave（ISW） and a traverse slender body at horizontal. The PIV technique is used to measure the varying flow field in the interaction process. The varying horizontal and vertical forces exerted by the ISW on the submerged body are measured by use of a three-component force-measuring sensor, and their influences of both incident wave amplitude and the body depth on the above forces are discussed. The experimental results have shown that ISWs can make a strong horizontal shear flow between upper and lower fluid layers. The horizontal velocity below the wave profile is smaller than the one in the upper-layer fluid, while the vertical flows at the front/back of the ISW are the descending/rising flows respectively. The horizontal force exerted on the submerged body is mainly determined by the wave-induced flow field, while the vertical force is depended on the coupling effect of both varying density and flow fields. In addition, when the ISW is incident on the traverse slender body, the large eddy occurring behind its back will results in a ball of fluid with higher density detaining as well as scattering. It is proved one of the important factors that decide the distinct forces exerted on the submerged slender body placed perpendicular or parallel to the direction of ISW’s propagation.