上海交通大学学报

上海交通大学学报（自然版） ›› 2018, Vol. 52 ›› Issue (8): 946-953.doi: 10.16183/j.cnki.jsjtu.2018.08.010

• 学报（中文） • 上一篇    下一篇

障碍物对平坡异重流运动特性的影响

吕亚飞1，赵亮1，贺治国1,2，林颖典1，袁野平1,2，胡鹏1   

  1. 1. 浙江大学 海洋学院， 浙江 舟山 316021； 2. 国家海洋局 第二海洋研究所， 杭州 310012
  • 收稿日期:2017-04-19
  • 通讯作者: 贺治国，男，教授，博士生导师，电话（Tel.）:13968116493； E-mail:hezhiguo@zju.edu.cn.
  • 作者简介:吕亚飞(1992-)，男，河南省邓州市人，硕士生，研究方向为异重流水动力实验.
  • 基金资助:
    国家重点研发计划（2017YFC0405502），浙江省自然科学基金(LR16E090001)，深圳市科技研发资金基础研究(2016-100)

Impacts of Obstacle on Gravity Currents Propagating Along a Flat Bed

LV Yafei,ZHAO Liang,HE Zhiguo,LIN Yingtien,YUAN Yeping,HU Peng   

  1. 1. Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China；2. The Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China
  • Received:2017-04-19

摘要： 在水利工程中，底床地形突变对异重流的运动过程有十分重要的影响.利用高速相机和激光粒子图像测速技术(PIV)，对开闸式盐水异重流在平坡定常速阶段遇到障碍物时的运动特性进行研究.实验结果表明，障碍物对异重流头部速度的作用范围约为5个闸室长，对异重流加速阶段头部速度最大值的减幅影响很小，仅为1%左右.当异重流厚度与障碍物高度相当时，异重流在环境水体中的最大作用高度值会增加近1倍，同等工况时，矩形断面下该值会比三角形断面下增大约20%.障碍物前、后和顶部3个特征断面处异重流能量和厚度达到最大值的时间不同步，厚度最大值的时刻比能量滞后1.5～2s.障碍物前、后特征断面处能量近似单峰分布，而顶部断面则为双峰分布.障碍物前断面最大厚度增大约20%，最大能量损失约40%.结果可为复杂地形水利环境下污染物的输移扩散、海底电缆保护、港池回淤等研究提供科学依据.

关键词: 异重流, 障碍物, 粒子图像测速, 速度场, 涡度场

Abstract: Obstacles on the bed have important impacts on the hydrodynamic behaviors of gravity currents in hydraulic engineering. In this paper, a high-speed camera and a laser particle image velocimetry (PIV) technique were applied to investigate the characteristics of lock-exchange gravity currents encountering different obstacles at the slumping stage on a flat bed. The experimental results show that the obstacle influenced the head velocity of gravity currents within about 5-lock length, while the reduction of maximum speed of the head before meeting the obstacle was small, with a value of about 1%. When the thickness of the gravity current was equal to the height of the obstacle, the maximum height of the gravity current on the environment may be nearly doubled. In the same condition, the height caused by the rectangular obstacle was about 20% larger than that by the triangle one. The time for the peak thickness of the gravity current at three characteristic sections (i.e. in front of, behind, and on the top of the obstacle) varied from 1.5 to 2s later than that for the energy. The energies at the characteristic sections in front of and behind the obstacle followed a unimodal distribution, while that at the top section followed a bimodal distribution. The peak thickness at the characteristic sections in front of the obstacle increased about 20%, but the peak energy decreased about 40%. The present results provide useful information for pollutant in water environment, submarine cable protection, and reservoir deposition, etc.

Key words: gravity current, obstacle, particle image velocimetry (PIV), velocity field, vorticity field

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