A laboratory study of the velocity structure in an intrusive gravity current
A laboratory study of the velocity structure in an intrusive gravity current
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侵入重力流中速度结构的实验室研究
DOI：
10.1017/s0022112001007303
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发表时间：
2000
影响因子：
3.7
通讯作者：
J. Rottman
中科院分区：
文献类型：
--
作者：
Ryan J. Lowe;P. Linden;J. Rottman
进行了实验室实验，其中使用阴影和粒子跟踪方法观察到侵入重力流。入侵是在一个两层流体中产生的，通过在垂直闸门后面混合流体，然后突然将闸门从罐中抽出，从而产生尖锐的界面。实验的目的是确定侵入体内部的速度场结构和界面的稳定性特征。闸门拆除后不久，侵入的重力流的前部以恒定的速度移动，接近理论预测的能量守恒重力流的值。所观察到的侵入体内部的流动结构可以分为三个区域。在侵入体的前部存在一个能量守恒的头部区域，在该区域中流体速度几乎是均匀的，速度等于前部速度。随后是一个耗散尾流区，其中存在大的波涛及其相关的混合，并且其中观察到流体速度是不均匀的，并且具有比前速度大约50%的最大速度。尾流区的后面是一个尾部区域，其中混合非常少，速度场几乎是均匀的，速度略快于前速度。
Laboratory experiments were performed in which an intrusive gravity current was observed using shadowgraph and particle tracking methods. The intrusion was generated in a two-layer fluid with a sharp interface by mixing the fluid behind a vertical lock gate and then suddenly withdrawing the gate from the tank. The purpose of the experiments was to determine the structure of the velocity field inside the intrusion and the stability characteristics of the interface. Soon after the removal of the lock gate, the front of the intrusive gravity current travelled at a constant speed close to the value predicted by theory for an energy-conserving gravity current. The observed structure of the flow inside the intrusion can be divided into three regions. At the front of the intrusion there is an energy-conserving head region in which the fluid velocity is nearly uniform with speed equal to the front speed. This is followed by a dissipative wake region in which large billows are present with their associated mixing and in which the fluid velocity is observed to be non-uniform and have a maximum speed approximately 50% greater than the front speed. Behind the wake region is a tail region in which there is very little mixing and the velocity field is nearly uniform with a speed slightly faster than the front speed.