分层流内波生成机理研究

发布时间：2018-04-29 04:25

本文选题：密度连续分层流体 + 内波　；参考：《上海交通大学》2015年硕士论文

【摘要】：最近二十年来,由于卫星遥感、图像识别等高技术的发展,探索海洋中物体运动尾迹及其与自由面干扰的探测技术已得到人们的关注。然而,密度连续分层并带有自由面的流场中物体运动导致的内波及自由面波动特征和机理既是个至今悬而未决的理论问题,同时又与物体尾迹强弱和遥感探测密切相关,无论在理论上还是实验技术上均有很大的研究难度,有进一步探索的必要。关于均匀连续分层流体中的内波生成格林函数已有不少的研究,但是结果互有出入。并且这些研究都是针对无限流场进行的,完全不考虑自由面的影响,也无从考察内波与自由面干扰机理。另一方面,国内外凡是涉及自由面的内波研究基本上都在密度间断分层的流场中进行,但从理论和实践上讲,密度间断分层产生的界面波与密度连续分层流体中产生的内波在本质上是两种不同的概念,涉及水气交界的自由面波动形态时尤其如此。本文主要是基础理论方面的研究,论文首先建立了带自由面密度连续分层流体中的内波方程,基于围道积分和傅里叶变换,分别给出了点源脉动频率大于和小于Brunt-V?is?l?频率两种情况下脉动点源格林函数的详细推导和最终的解析表达式,并进而讨论了内波机理和自由面波动特征,为进一步开展连续分层流中物体运动内波生成和自由面波动特征研究奠定基础。
[Abstract]:In the last two decades, due to the development of satellite remote sensing, image recognition and other high technology, the detection technology of moving wake and its interference with free surface in the ocean has been paid more and more attention. However, the characteristics and mechanism of the internal wave and free surface fluctuation caused by the motion of an object in a flow field with continuous stratification of density and free surface are not only a pending theoretical problem, but also closely related to the wake strength of the object and the detection of remote sensing. Both in theory and experimental technology, there is a great difficulty in research, and it is necessary to further explore. The Green's function of internal wave generation in homogeneous continuous stratified fluid has been studied, but the results are different. Moreover, these studies are aimed at the infinite flow field and do not consider the influence of free surface at all, nor can we study the mechanism of internal wave and free surface interference. On the other hand, the internal wave research involving free surface at home and abroad is basically carried out in the flow field with density discontinuous stratification, but theoretically and practically speaking, The interfacial waves generated by density discontinuous stratification are essentially two different concepts from the internal waves generated in dense continuous stratified fluids, especially when the free surface waves at the boundary of water and gas are involved. In this paper, the internal wave equation of continuous stratified fluid with free surface density is established. Based on the channel integral and Fourier transform, the pulsation frequency of point source is obtained, which is greater than or less than Brunt-Vissil? The detailed derivation and final analytical expression of the Green's function of pulsating point source in two cases of frequency are given, and the mechanism of internal wave and the characteristics of free surface wave are discussed. It lays a foundation for further research on the generation of moving internal waves and the characteristics of free surface waves in continuous stratified flow.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P731.24

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