圆桩柱对斜坡异重流动力特性影响的研究  

Impacts of a circular pile on hydrodynamics of downslope gravity current

作　　者：林颖典 叶漪琦 韩东睿 陈甫源 LIN Yingdian;YE Yiqi;HAN Dongrui;CHEN Fuyuan(Key Laboratory of Estuary and Coast of Zhejiang Province,Hangzhou 310020,China;Ocean College,Zhejiang University,Zhoushan 316021,Zhejiang China)

机构地区：[1]浙江省河口海岸重点实验室,浙江杭州310020 [2]浙江大学海洋学院,浙江舟山316021

出　　处：《华中科技大学学报（自然科学版）》2023年第8期93-101,共9页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：浙江省河口海岸重点实验室开放基金资助项目(ZIHE21002);浙江省自然科学基金资助项目(LY20A020009)。

摘　　要：为探究圆柱桩对斜坡异重流动力特性的影响,开展一系列开闸式斜坡异重流的水槽实验,通过高速相机记录异重流宏观传播过程,并结合粒子图像测速(PIV)技术量化局部流场特性,分析不同圆柱桩的高度及倾斜角度下异重流的运动.实验结果表明:流经圆桩柱时,异重流头部逐渐抬升,尾部加厚;圆桩柱改变了异重流展向扩散模式,使其前缘分布更加不均匀.异重流流过圆桩柱产生的马蹄涡及尾流漩涡会提升整体卷吸系数的峰值,并使异重流在交界面处的涡旋结构变得更加复杂.异重流的中心区是涡旋生成和发展的核心位置,圆桩柱的高度决定异重流的越流形态,从而影响涡度场的分布.圆桩柱提高了局部湍流强度,圆柱桩变高,异重流湍动能的峰值会随时间前移.对于非浸没式圆桩柱,倾斜角度降低了桩前区域异重流的湍流水平,并且桩后的湍动能随时间由单峰态演变为多峰态.To understand the impacts of a circular pile on the hydrodynamics of downslope gravity current,a series of lockexchange experiments were carried out to analyze the current motions with different height and inclined angle of the pile.The macroscopic propagation process of the gravity current was recorded by using a high-speed camera,and the local flow field characteristic was quantified by combining the particle imaging velocimetry(PIV)technique.The results show that when the gravity current flows through the circular pile,its head is gradually lifted and tail is thickened.The existence of the circular pile changes the spanwise diffusion pattern of the gravity current,making its leading edge distribution more uneven.Horseshoe vortex and wake vortex generated by gravity current flowing through a circular pile increase the peak value of the overall entrainment coefficient and complicate the vortex structure of gravity current at the current-ambient fluid interface.The central area of the gravity current is the core position of the vortex generation and development.The height of the circular pile determines the over-flowing shape of the gravity current and thus affects the distribution of its vorticity field.The circular pile increases the local turbulent intensity,and the higher circular pile leads to the peak value of turbulent kinetic energy(TKE)of the current occurring in advance.For a emergent circular pile,the inclined angle reduces the turbulence level of the gravity current in the front of the pile,and the TKE behind the pile becomes multi-peak pattern with time instead of the original single peak.

关 键 词：异重流 圆桩柱 卷吸过程 尾流 湍动能 

分 类 号：TV145[水利工程—水力学及河流动力学]