| 摘要: |
| 为进一步探究海洋内孤立波诱导流场对海洋工程结构物以及潜航器的影响, 本文采用重力塌陷方法和粒子图像测速(Particle Image velocimetry, PIV)技术在大型分层流水槽中进行内孤立波造波以及内部流速场测量, 定量分析了下凹型内孤立波诱导流场结构及其影响因素。研究表明: 在密度分层流体中, PIV技术可实现对大幅面内孤立波诱导流场的精细测量以及波动结构特征的准确描述; 水平流速在上下层方向相反且在跃层处最小, 其剪切作用在波谷附近最强; 垂向流动在波前和波后分别为上升和下沉流, 两者流速值在距离波谷1/4～1/2波长位置达到最大; 在相同内孤立波振幅条件下, 上下层流体密度差越大、厚度比越小, 则波致流场越强; 随着振幅增大, 流场结构与KdV、eKdV 和MCC理论模型对应波幅适用范围的描述相吻合。 |
| 关键词: 分层流 内孤立波 粒子图像测速(Particle Image velocimetry, PIV)技术 流场特性 水槽实验 |
| DOI：10.11759/hykx20170404001 |
| 分类号: |
| 基金项目:国家自然科学基金项目(11472307); 国防技术基础项目(QX2015043104A12002) |
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| Experimental study on the flow field induced by internal solitary waves and its influence factors |
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WU Jun-lin,WEI Gang,DU Hui,XU Jun-nan
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| Abstract: |
| To study the influence of the flow field induced by internal solitary waves (ISWs) on marine engineering structures and underwater vehicles, in a large-scale gravity-stratified fluid tank, the velocities of a series of ISWs created by gravity collapse were measured using particle image velocimetry (PIV) and its wave-induced flow field and influence factors were quantitatively analyzed. Experimental results show that the PIV technique can realize the fine measurement for the flow field induced by the large-scale solitary wave in the density-stratified fluid. The direction of the horizontal velocity below the wave profile is opposite to the one in the upper-layer fluid and the minimum velocity appears at the pycnocline, whereas the horizontal shear is the strongest near the pycnocline. The vertical flows at the front and rear of the ISWs are the descending and ascending flows, respectively, and achieve their maximums at a position that is 1/4–1/2 times the wavelength away from the trough. The velocity values at the same amplitude increase with increasing differences of density and thickness between the upper and lower layers. Moreover, as the amplitude increases, the flow field structures successively coincide with the description of the KdV, eKdV, and MCC theoretical models in their applicable ranges. |
| Key words: stratified fluid internal solitary wave PIV flow field experiments in water tank |
