| 摘要: |
| 采用重力塌陷方法和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准确描述波动结构的特征；水平流速在上下层方向相反且在跃层处最小,水平剪切在波谷附近最强；垂向流动在波前、后分别为上升和下沉流,两者在距离波谷1/4-1/2波长位置取得最大值；在相同内孤立波振幅条件下,上下层流体密度差愈大、厚度比愈小,则波致流场愈强；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 PIV技术 流场特性 水槽实验 |
| DOI：10.11759/hykx20170407001 |
| 分类号:P731.1 |
| 基金项目:国家自然科学(11472307)和国防技术基础项目(QX2015043104A12002) |
|
| Experimental study on the flow field induced by internal solitary wave and its influence factors |
|
WU Jun-lin,WEI Gang,Du Hui and Xu Jun-nan
|
|
College of Meteorology and Oceanography，National University of Defense Technology,College of Meteorology and Oceanography，National University of Defense Technology,College of Meteorology and Oceanography，National University of Defense Technology,College of Meteorology and Oceanography，National University of Defense Technology
|
| Abstract: |
| In a large-type gravity stratified fluid tank , velocities of a series of internal solitary waves (ISWs) created by gravity collapse were measured with the Particle Image Velocimetry (PIV) technique and its wave-induced flow field and influence factors have been analyzed quantitatively. The experimental results have shown 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 horizontal velocity below the wave profile is opposite to the one in upper-layer fluid and the minimum velocity appears at the pycnocline, while the horizontal shear is the strongest near the pycnocline. The vertical flows at the front/rear of the ISWs are the descending / rising flows respectively and achieve their maximums at the position of 1/4-1/2 times wavelength away from the trough. The velocity values in the same amplitude increase with the increase of the difference of the density and thickness between the upper and lower layers. Moreover, as the amplitude increases the flow field structures coincide with the description of the KdV, eKdV and MCC theoretical models in their applicable ranges successively. |
| Key words: stratified fluid internal solitary wave PIV velocity field experiments in water tank |