连续密度跃层中第二模态内孤立波及其波致流场实验研究  

Experimental Investigation on Mode-2 Internal Solitary Wave and its Induced Flow Field in Continuous Density Pycnocline

作　　者：王少东 杜辉 彭湃 宣谱 王观景 陆哲宇 魏岗 Wang Shaodong;Du Hui;Peng Pai;Xuan Pu;Wang Guanjing;Lu Zheyu;Wei Gang(College of Meteorology and Oceanography,National University of Defense Technology,Changsha 410000,China)

机构地区：[1]国防科技大学气象海洋学院,长沙410000

出　　处：《水动力学研究与进展（A辑）》2024年第1期66-72,共7页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金(11902352);湖南省科技创新计划(2023RC3005)。

摘　　要：该文在大型分层流水槽中开展了连续密度跃层中第二模态内孤立波及其波致流场的实验研究。利用分层流体重力塌陷原理,该文实验模拟了连续密度跃层中“上凸下凹”型的第二模态内孤立波,利用电导率探头阵列和粒子图像测速技术测量第二模态内孤立波及其波致流场,获得了连续密度跃层中充分发展第二模态内孤立波的几何与波-流场非均匀结构,以及波幅变化对第二模态内孤立波的波要素关系和波致流场特征的影响。研究结果表明:连续密度跃层中,第二模态内孤立波波形几何特征表现为上凸下凹的卵形波包状,波形非均匀垂向结构特征表现为波幅和波长随深度的非均匀变化;第二模态内孤立波波包上凸与下凹域分别形成逆时针和顺时针环流,两者组合为一对上下反对称的环流并共同向前传播;第二模态内孤立波波速随波幅的增大而增大,波长则随波幅的增大而减小;水平和垂向流速强度与特征波幅呈正相关关系,且水平流速强度大于垂向流速强度。该文提升了对实际海洋层化条件下第二模态内孤立波及其波致流场的认识。The experimental investigation on the Mode-2 internal solitary waves(ISW)and its induced flow field in the continuous density pycnocline are carried out in a large stratified flume.The experimental simulation of the Mode-2 ISW in the continuous pycnocline is realized by using the principle of stratified fluid gravity collapse.The conductivity probe array and particle image velocimetry(PIV)are used to measure the Mode-2 ISW and its wave induced flow field.The geometrical characteristics of Mode-2ISW waveform in the continuous pycnocline is obtained,and the non-uniform structures of the wave-flow are obtained,and the influence of wave amplitude variation on the characteristics of wave propagation factor and wave-flow field of Mode-2 ISW are obtained.The research shows that the geometric waveform of the Mode-2 ISW in the continuous pycnocline is presented as the convex and concave oval wave packets,and the non-uniform vertical structure of waveform is characterized by the non-uniform changes of the amplitude and wavelength with water depth.The convex and concave regions of the Mode-2 ISW packet form counterclockwise and clockwise circulations respectively,and the combination of the two forms a pair of upper and lower antisymmetric circulations to propagate forward together.The wave velocity of the Mode-2 ISW increases with the increase of wave amplitude,and the wavelength decreases with the increase of wave amplitude.The magnitudes of the horizontal and vertical flow velocity are positively correlated with the characteristic wave amplitude,and the former magnitude is greater than the latter one.The research results can improve the understanding of the Mode-2 ISW and its wave-induced flow field under the actual ocean stratification conditions.

关 键 词：连续密度跃层 第二模态内孤立波 非均匀垂向结构 波致流场 

分 类 号：TU476[建筑科学—结构工程]