吉林大学学报(地球科学版) ›› 2019, Vol. 49 ›› Issue (6): 1714-1722.doi: 10.13278/j.cnki.jjuese.20180220

• 地质工程与环境工程 • 上一篇    下一篇

在层结和非层结环境下植被群对异重流运动的影响

林颖典, 刘雅钰, 袁野平   

  1. 浙江大学海洋学院, 浙江 舟山 316000
  • 收稿日期:2018-06-20 发布日期:2019-11-30
  • 作者简介:林颖典(1976-),男,副教授,博士,主要从事异重流研究,E-mail:kevinlin@zju.edu.cn
  • 基金资助:
    国家自然科学基金项目（11672267）；国家重点研发计划项目（2017YFC0405502）

Effect of Vegetation Patch on Gravity Current Movement in Stratified and Non-Stratified Environments

Lin Yingtien, Liu Yayu, Yuan Yeping   

  1. Ocean College, Zhejiang University, Zhoushan 316000, Zhejiang, China
  • Received:2018-06-20 Published:2019-11-30
  • Supported by:
    Supported by National Natural Science Foundation of China(11672267) and National Key R & D Program of China (2017YFC0405502)

PDF (PC)

310

摘要： 异重流在自然环境界及工程应用中广泛存在。本文于线性层结及非层结盐水中开展了一系列实验，对开闸式异重流通过植被群的发展和演变特性进行了研究。采用高速相机对异重流头部位置、头部速度和掺混系数等进行了分析，结果表明：异重流在层结水体中头部速度明显减小；层结水体和植被对异重流掺混均有抑制作用；当层结水体和植被同时存在时，异重流的掺混程度与植被高度和水深之比α相关，当α=0.43时，异重流的掺混最为剧烈。本研究也利用粒子图像测速仪（particle image velocimetry，PIV）对异重流局部区域的速度场和涡度场进行研究，结果显示，层结环境抑制异重流正负涡度场发展，但当α=0.20时，即一部分异重流爬上植被顶部时，层结水体与植被的协同效应对跃上植被顶端的异重流下界面涡度有强化作用。

关键词: 异重流, 层结水体, 植被群, 粒子图像测速仪

Abstract: Gravity currents exist widely in nature and engineering. In this study, a series of laboratory experiments were conducted to investigate lock-release gravity currents through vegetation patches into different ambient environments. The head position, front velocity and entrainment coefficient of gravity currents were analyzed by using the images acquired by a high-speed camera. The results show that the front velocity in linearly stratification environments is smaller than that in constant-density ambient. Both stratified environment and vegetation patches can inhibit the entrainment between gravity current and ambient water. As stratified environment and vegetation patches exist simultaneously, the mixing and entrainment of gravity currents are related to the ratio α of vegetation height to water depth. When α=0.43, the entrainment and mixing between gravity current and ambient water are the strongest. The particle image velocimetry (PIV) technique was applied to study the velocity and vorticity fields in detail. The results show that the stratification environment can restrain the development of the vorticity both at the upper and lower interfaces between current and ambient water. However, when α=0.20, i.e. some gravity currents climbs to the top of vegetation patches, the combined effects of the stratified water and the vegetation patch strengthen the vorticity near the top of vegetation patches.

Key words: gravity current, stratified water, vegetation patch, particle image velocimetry

中图分类号: 

  • P75
[1] 范家骅. 异重流与泥沙工程实验与设计[M].中国水利水电出版社, 2011. Fan Jiahua. Density Currents and Sedimentation Engineering Experiments and Design[M]. China Water Resources and Hydropower Publishing House, 2011.
[2] 贾复, 吴乃华, 张伯寅. 分层流体中异重流的流态研究[J]. 水动力学研究与进展, 1986, 1(2):67-73. Jia Fu, Wu Naihua, Zhang Boyin. Study on Flow Patterns of Different Heavy Flows in Stratified Fluids[J]. Advance in Hdrodynamics, 1986, 1(2):67-73.
[3] 林挺. 层结水体中异重流沿坡运动的试验研究[D]. 杭州:浙江大学, 2016. Lin Ting. Experimental Study on the Movement of Gravity Currents Along a Slope in a Stratified Water Body[D]. Hangzhou:Zhejiang University, 2016.
[4] 范家骅. 异重流运动的实验研究[J]. 水利学报, 1959(5):32-50. Fan Jiahua. Experimental Study on the Movement of Different Gravity Flow[J]. Journal of Hydraulic Engineering, 1959(5):32-50.
[5] Dorrell R M, Darby S E, Peakall J, et al. The Critical Role of Stratification in Submarine Channels:Implications for Channelization and Long Runout of Flows[J]. Journal of Geophysical Research Oceans, 2014, 119(4):2620-2641.
[6] Tokyay T E, García M H. Effect ofInitia Excess Density and Discharge on Constant Flux Gravity Currents Propagating on a Slope[J]. Environmental Fluid Mechanics, 2014, 14(2):409-429.
[7] Dai A. Experiments on Gravity Currents Propagating on Different Bottom Slopes[J]. Journal of Fluid Mechanics, 2013, 731:117-141.
[8] Shin J O, Dalziel S B, Linden P F. Gravity Currents Produced by Lock Exchange[J]. Journal of Fluid Mechanics, 2004, 521:1-34.
[9] Benjamin T B. Gravity Currents and Related Phenomena[J]. Journal of Fluid Mechanics, 1968, 31(2):209-248.
[10] Ozan A Y, Constantinescu G, Hogg A J. Lock-Exchange Gravity Currents Propagating in a Channel Containing an Array of Obstacles[J]. Journal of Fluid Mechanics, 2015, 765:544-575.
[11] 贺治国, 林挺, 赵亮,等. 异重流在层结与非层结水体中沿斜坡运动的实验研究[J]. 中国科学:技术科学, 2016, 46(6):570. He Zhiguo, Lin Ting, Zhao Liang, et al. Experiments on Gravity Currents Down a Ramp in Unstratified and Linearly Stratified Salt Water Environments[J]. Scientia Sinica:Tchnologica, 2016, 46(6):570.
[12] Guo Y, Zhang Z, Shi B. Numerical Simulation of Gravity Current Descending a Slope into a Linearly Stratified Environment[J]. Journal of Hydraulic Engineering, 2014, 140(12):04014061.
[13] Maxworthy T, Leilich J, Simpson J E, et al. The Propagation of a Gravity Current into a Linearly Stratified Fluid[J]. Journal of Fluid Mechanics, 2002, 453(3):371-394.
[14] Cenedese C, Nokes R, Hyatt J. Lock-Exchange Gravity Currents over Rough Bottoms[J]. Environmental Fluid Mechanics, 2016,18:1-15.
[15] 赵亮, 吕亚飞, 贺治国, 等. 分层水体和障碍物对斜坡异重流运动特性的影响[J]. 浙江大学学报(工学版), 2017, 51(12):2466-2473. Zhao Liang, Lü Yafei, He Zhiguo, et al. Influence of Stratified Water and Obstacles on Downslope Gravity Currents' Movement Characteristics[J]. Journals of Zhejiang University (Engineering Science), 2017,51(12):2466-2473.
[16] 夏景生,王志坤,王海荣,等. 渤海湾盆地南堡凹陷西斜坡中深层"混合型河口坝"成因及沉积学意义[J]. 吉林大学学报(地球科学版), 2017, 47(6):1642-1653. Xia Jingsheng,Wang Zhikun,Wang Hairong,et al. Blended Mouth Bars' Cause and Sedimentary Significance of Middle-Deep Beds in Western Slope of Nanpu Sag,Bohai Bay Basin[J]. Journal of Jilin University (Earth Science Edition),2017,47(6):1642-1653.
[17] Ghajar A J, Bang K. Experimental and Analytical Studies of Different Methods for Producing Stratified Flows[J]. Energy, 1993, 18(4):323-334.
[18] Fortuin J M H. Theory and Application of Two Supplementary Methods of Constructing Density Gradient Columns[J]. Journal of Polymer Science:Part A:Polymer Chemistry, 1960, 144:505-515.
[19] Huppert H E, Simpson J E. The Slumping of Gravity Currents[J]. Journal of Fluid Mechanics, 2006, 99(4):785-799.
[20] Thielicke W, Stamhuis E J. PIVlab-Towards User-Friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB[J/OL]. Journal of Open Research Software, 2014, 2(1).[2018-01-10]. https://openresearchsoftware.metajnl.com/article/10.5334/jors.bl/.
[21] Ungarish M. On Gravity Currents in a Linearly Stratified Ambient:A Generalization of Benjamin's Steady-State Propagation Results[J]. Journal of Fluid Mechanics, 2006, 548:49-68.
[22] Baines P G. Mixing in Flows down Gentle Slopes into Stratified Environments[J]. Journal of Fluid Mechanics, 2001, 443:237-270.
[23] Jacobson M R, Testik F Y. Turbulent Entrainment into Fluid Mud Gravity Currents[J]. Environmental Fluid Mechanics, 2014, 14(2):541-563.
[24] Wilson R I, Friedrich H, Stevens C. Turbulent Entrainment in Sediment-Laden Flows Interacting with an Obstacle[J]. Physics of Fluids, 2017, 29(3):036603.
[25] Ottolenghi L, Adduce C, Inghilesi R, et al. Entrainment and Mixing in Unsteady Gravity Currents[J]. Journal of Hydraulic Research, 2016, 54(5):1-17.
[26] Samothrakis P, Cotel A J. Propagation of a Gravity Current in a Two-Layer Stratified Environment[J]. Journal of Geophysical Research Oceans, 2006, 111(C1):C01012.
[1] 夏景生, 王志坤, 王海荣, 薛林, 王恺, 刘成权. 渤海湾盆地南堡凹陷西斜坡中深层“混合型河口坝”成因及沉积学意义[J]. 吉林大学学报(地球科学版), 2017, 47(6): 1642-1653.
Viewed
Full text


Abstract

Cited
  Shared   
  Discussed   
No Suggested Reading articles found!
版权所有 © 《吉林大学学报(地球科学版)》编辑部
地址：长春市西民主大街938号(130026)　电话：+86-431-88502374；13756165364　E-mail: xuebao1956@jlu.edu.cn
本系统由北京玛格泰克科技发展有限公司设计开发