海洋内孤立波斜相互作用的Mach效应特性实验  

Characteristics of Mach effect induced by oblique wave-wave interactions of internal solitary waves in ocean

作　　者：王欣隆 魏岗[1] 杜辉[1] 谷梦梦 王彩霞[2] 

机构地区：[1]解放军理工大学气象海洋学院,南京211101 [2]中国海洋大学海洋环境学院,青岛266100

出　　处：《科学通报》2016年第4期529-535,共7页Chinese Science Bulletin

基　　金：国家自然科学基金(11472307);国防基础科学研究计划(QX2015043104A12002)资助

摘　　要：当海洋工程结构物或水下航行器在海洋中遭遇异常大振幅内波时可造成损害甚至失事,海洋内孤立波斜相互作用的Mach效应是一种特殊海洋现象,也是异常大振幅内孤立波的重要成因.为了在实验室模拟具有海洋跃层环境中的内孤立波斜相互作用并控制Mach效应的产生,首先将两只直立无底圆柱筒放置在淡/盐水分布的两层流体环境中,淡/盐水混合区模拟海洋密度跃层,保持筒底与筒外水体的交换,以方便形成筒内外混合区的高度差;再将两柱筒平稳迅速移出,利用柱筒内外淡/盐水混合区高度差的重力塌陷扰动形成两列内孤立波,其在交汇区发生斜相互作用,并借助高清图像处理技术结合几何射线方法完成测量.实验结果表明:两列内孤立波斜相互作用性质取决于分层环境、两柱筒之间距离以及两列内孤立波的波幅和相位,上述方法可有效控制分层流实验水槽中Mach效应的产生.进一步分析表明:两列内孤立波相互作用的Mach效应将导致波幅显著增强,传播速度明显增大,且传播方向受两者振幅大小的控制,振幅相差越大所产生Mach效应的临界夹角越大.此外,通过内孤立波斜相互作用的Mach效应实验结果与Kd V,BO和MCC三种理论模型的比较,实验验证了Mach效应对非线性理论模型的适应性.The Mach effect induced by the oblique wave-wave interactions of internal solitary waves is a special phenomenon of the ocean and is also the main reason of generating a large amplitude internal solitary wave, while they can cause it damage and even crash as the ocean engineering structures or underwater vehicles encounter the internal solitary wave with a large ampiltude in the ocean. In order to simulate the oblique interaction of internal solitary waves in the thermocline marine environment and control the Mach effect in the laboratory, two vertical bottomless barrels are placed in the fresh/saline water＇ s two-layer fluid. So the mixed fresh/saline water region is called the density thermocline of the marine. Keeping exchange of water under the barrel＇s bottoms is to facilitate the formation of the mixed region height difference in the inner and outer parts of barrels. And then remove the two barrels smoothly and quickly, so that the mixed fresh/saline water region＇s gravitational collapse motion can be made use of to generate two rows of internal solitary waves. They will occur the oblique wave-wave interaction in their propagating intersection area. The experimental results showed that two rows of solitary wave oblique interaction depends on the stratification environment, the distance between the two barrels and the amplitude and phase of two solitary waves. It has been verified that the above method can effectively control the generation of Mach effect in the stratified fluid tank. Further analysis showed that the Mach effect induced by the oblique interaction of internal solitary waves will lead to remarkably increasing amplitude in correspondence with its raising propagation velocity, whose direction is controlled by the amplitude difference between two internal solitary waves, and the greater amplitude difference will bring on the larger Mach effect＇s critical angle. Through testing the theoretical models including KdV＇, BO＇ and MCC＇s equations to compare with the experimental results, th

关 键 词：分层流 内孤立波 斜相互作用 Mach效应 水槽实验 

分 类 号：P731.2[天文地球—海洋科学]