南海内孤立波的演变特性及对结构物的作用力  

Evolution characteristics of internal solitary waves in the South China Sea and their forces on structures

作　　者：刘倩 崔健[1] 张瑞瑞[1] 梅欢 吴祥柏 高俊亮[1] LIU Qian;CUI Jian;ZHANG Ruirui;MEI Huan;WU Xiangbai;GAO Junliang(School of Naval Architecture and Ocean Engineering,Jiangsu University of Science and Technology,Zhenjiang 212100,China)

机构地区：[1]江苏科技大学船舶与海洋工程学院,江苏镇江212100

出　　处：《哈尔滨工程大学学报》2024年第11期2100-2108,共9页Journal of Harbin Engineering University

基　　金：江苏省自然科学基金青年基金项目(BK20210885);国家自然科学基金面上项目(42076005)

摘　　要：针对内孤立波引发的高强度流场易影响海洋平台正常工作的问题,本文基于南海北部陆架区获得的高质量的海流和温盐数据,对观测海区内孤立波的演变特征进行了研究。研究结果显示:观测海区内孤立波活动频繁,且具有明显的第一模态下凹型内孤立波特征。内孤立波经过时,在50~100 m以上的上层诱发了较强的西向流速,其大小接近0.44 m/s,在深度超过100 m则为东向补偿流为主,东向补偿流的量值与西向流相比较小。在垂向上,波前的水体向下流动,波后的水体则向上流动,最大垂向流速可达0.2 m/s。内孤立波引起的向下的等温线的起伏达到50 m。此外,基于计算流体力学软件Fluent对观测海区内孤立波进行模拟,并计算内孤立波对桩柱的作用力。结果表明:数值模拟得到的内孤立波与实测内孤立波吻合较好,内孤立波对桩柱的水平作用力和垂向作用力主要受到压差力的影响,且以水平作用力占主导,上层桩柱受力为-60 kN,下层桩柱受力为20 kN。本文研究结果不仅对陆架区内孤立波的特征有进一步的认识,同时对南海内孤立波的预报及对海洋结构物设计等具有一定的指导价值。The high-intensity flow field resulting from internal solitary waves(ISWs)can easily influence the normal operation of marine platforms.This paper studies the evolution characteristics of ISWs in the observed sea area based on high-quality current,temperature,and salinity data obtained from the northern shelf area of the South China Sea.The results reveal that the ISWs in the observed sea area are frequently active and have obvious characteristics of mode-1 concave ISWs.When ISWs pass through the shallow upper layer of 50~100 m,the waves induce a strong westward flow velocity with a magnitude of nearly 0.44 m/s.At a depth of 100 m,the waves are primarily an eastward compensated flow,with the magnitude of the eastward compensated flow being relatively small compared with the westward flow.In the vertical direction,the water in front of the wave flows downward,while that behind the waves flows upward,with a maximum vertical velocity of 0.2 m/s.The downward isotherm fluctuation caused by ISWs reaches 50 m.Moreover,the ISWs in the observed sea area are simulated using the Fluent software,and the forces exerted by the ISWs on the pile are calculated.The results disclose that the simulated ISWs agree well with the calculated ISWs.The horizontal and vertical forces of the ISWs on the pile are mainly influenced by the pressure differential force,and the horizontal force dominates.The force on the upper pile is-60 kN,and that on the lower pile is 20 kN.Thus,this study not only furthers our understanding of the characteristics of ISWs in the continental shelf region but also offers a reference for predicting ISWs in the South China Sea and designing marine structures.

关 键 词：南海 内孤立波 声学多普勒流速剖面仪 结构物 数值模拟 计算流体力学 作用力 桩柱 

分 类 号：TV13[水利工程—水力学及河流动力学]