Suarface Effects of Internal Wave Generated by a Moving Source in a Two-Layer Fluid of Finite Depth
-
摘要: 基于水波动力学势流理论,以二流体系统中点源运动为基本模型,采用Green函数法,研究了分层流体中内部扰动诱生的内波对自由面的影响,探讨对合成孔径雷达成像起重要作用的自由面辐散场的变化规律。研究表明:当上下层流体密度跃变较大、源接近密跃层且Froude数Fr接近内波模式的临界值Fr2时,内波模式导致的自由面辐散场强度与表面波模式的贡献相当,两者具有强烈的耦合作用,理论分析与实验结果定性一致。Abstract: Based on the potential flow theory of water waves, the interaction mechanism between the free-surface and internal waves generated by a moving point source in the lower layer of a two-layer fluid was studied. By virtue of the method of Green. s function, the properties of the divergence field at the free surface were obtained, which plays an important role in the SAR image. It is shown that the coupling interaction between the surface-wave mode and internal-wave mode must be taken into account for the cases of large density difference between two layers, the source approaching to the pynocline and the total Froude number Fr close to the critical number Fr2. The theoretical analysis is qualitatively consistent with the experimental results presented by Ma Hui-yang.
-
Key words:
- internal wave /
- surface wave /
- stratified fluid /
- divergence field /
- wave-wave interaction
-
[1] MENG Jun-min. The simulation of the SAR image of internal solitary waves in Alboran seas[J]. J Hydrodynamics, Ser B,2001,3:88-92. [2] 戴世强. 一个二流体系统中两对孤立波的相互作用[J]. 中国科学A辑, 1983, (11): 1007-1017. [3] Lamb H.Hydrodynamics[M]. Sixth Edition. Cambridge University Press, 1932. [4] Wehausen J V,Laitone E V. Surface Wave[M]. Handbuch der Physik 9,Berlin,1960. [5] Chomaz J M. The structure of the near wake of a sphere moving horizontally in a stratified fluid[J]. J Fluid Mech, 1993,254: 1-21. [6] 马晖扬.分层流体中运动物体与自由面相互作用的实验研究[J].流体力学实验与测量, 2000,14(3):7-11. [7] Lighthill J. Waves in Fluid[M].Cambridge:Cambridge University Press, 1978. [8] Keller J B, Munk W H. Internal wave wakes of a body moving in a stratified fluid[J]. Phys Fluids,1970,13: 1452-1431. [9] Miles J W. Internal waves generated by a horizontally moving source[J].Physical Fluid Dynamics,1970, 2: 63-87. [10] Sharman R D,Wurtele M D. Ship waves and Lee waves[J].J Atmos Sci,1983,40: 396-427. [11] Phillps O M. The Dynamatics of the Dynamics of Upper Ocean[M]. Cambridge: Cambridge University Press,Second Edition,1977. [12] YIH Chia-shun, ZHU Song-ping.Pattern of ship waves[J]. Quar Appl Math,1989,47(1):17-33. [13] Hudimac A A. Ship waves in a stratified ocean[J]. J Fluid Mech 1961,11:229-243. [14] Crapper G D. Ship waves in a stratified ocean[J]. Fluid Mech, 1967, 29: 667-672. [15] Yeung R W, Nguyen T C. Waves generated by a moving source in a two-layer ocean of finite depth[J]. J Eng Math, 1999, 35: 85-107. [16] Alpers W, Hennings I. A theory of the imaging mechanism of underwater bottom topography by real and synthetic aperture radar[J].J Geophysical Research, 1984,89(C6):10529-10546. [17] Alpers W. On the detectability of ocean surface waves by real and synthetic aperture radar[J]. J Geophys Res, 1981,86: 6481-6498. [18] Stefanick T. The nonacoustic detection of submarine[J]. Scientific American, 1988,258: 41-47. [19] Stewart R H. Methods of Satellite Oceanography[M]. University of California Press, 1985. [20] 郭华东. 雷达对地观测理论与应用[M].北京:科学出版社, 2001. [21] Lin J T,Pao Y H.Wakes in stratified fluid[J]. Ann Rev Fluid Mech,1979, 11: 317-338. [22] Kallen E. Surface effects of vertically propagating gravity waves in a stratified fluid[J].J Fluid Mech,1986,182: 111-125.
点击查看大图
计量
- 文章访问数: 2374
- HTML全文浏览量: 121
- PDF下载量: 739
- 被引次数: 0