The unsteady overtopping of barriers by gravity currents and dam-break flows
The unsteady overtopping of barriers by gravity currents and dam-break flows
复制标题
重力流和溃坝水流不稳定越过障碍
作者：
Edward W. G. Skevington;A. Hogg
摘要利用浅水运动模型，结合复杂的边界条件，研究了重力驱动的水平流与障碍物的碰撞。边界条件允许几种越顶模式：超临界，亚临界和阻塞流。该模型进行了数学和数值分析，以揭示方面的不稳定的运动，并计算被困在上游的障碍物的流体的比例。几个问题的治疗。首先，分析了均匀入射电流的理想化问题，对非定常动力学区域进行了分类。然后，处理非常近或非常远的障碍物的极端状态，显示通过越顶模式的相互作用的进展。接下来，在后期的流体被困体积进行了数值研究，演示制度中的体积是纯粹由体积的考虑，和其他瞬态惯性效应是显着的。对于Boussinesq重力流，即使障碍物后的封闭区体积等于流体体积，仍有30%的流体逸出，要使溢出体积可以忽略不计，必须有3倍大的封闭区体积。对于陆上溃坝水流，当封闭体积等于流体体积时，逃逸的比例超过60%，并且需要与初始释放高度一样高的障碍物以使漫顶可以忽略不计。最后，我们将我们的预测与实验进行比较，在一系列参数上显示出良好的一致性。
Abstract The collision of a gravitationally driven horizontal current with a barrier following release from a confining lock is investigated using a shallow water model of the motion, together with a sophisticated boundary condition capturing the local interaction. The boundary condition permits several overtopping modes: supercritical, subcritical and blocked flow. The model is analysed both mathematically and numerically to reveal aspects of the unsteady motion and to compute the proportion of the fluid trapped upstream of the barrier. Several problems are treated. Firstly, the idealised problem of a uniform incident current is analysed to classify the unsteady dynamical regimes. Then, the extreme regimes of a very close or distant barrier are tackled, showing the progression of the interaction through the overtopping modes. Next, the trapped volume of fluid at late times is investigated numerically, demonstrating regimes in which the volume is determined purely by volumetric considerations, and others where transient inertial effects are significant. For a Boussinesq gravity current, even when the volume of the confined region behind the barrier is equal to the fluid volume, $30\,\%$ of the fluid escapes the domain, and a confined volume three times larger is required for the overtopped volume to be negligible. For a subaerial dam-break flow, the proportion that escapes is in excess of $60\,\%$ when the confined volume equals the fluid volume, and a barrier as tall as the initial release is required for negligible overtopping. Finally, we compare our predictions with experiments, showing a good agreement across a range of parameters.
溃坝反射
DOI：
10.1093/qjmam/hbab010
发表时间：
2021
期刊：
The Quarterly Journal of Mechanics and Applied Mathematics
影响因子：
--
作者：
Hogg A
通讯作者：
Hogg A
通道中的持续重力流
影响因子：
3.7
作者：
Hogg A
通讯作者：
Hogg A