The numerical simulation of atmospheric gravity currents. Part II. Environments with stable layers
The numerical simulation of atmospheric gravity currents. Part II. Environments with stable layers
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DOI：
10.1080/03091928908208903
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发表时间：
1989-06
影响因子：
1.3
通讯作者：
Sabine Haase;Roger K. Smith
中科院分区：
文献类型：
--
作者：
Sabine Haase;Roger K. Smith
第一部分介绍的大气重力流二维数值模式被用来研究环境低层稳定层对重力流演变的影响。这在气氛中是很常见的情况，但在文学中似乎很少受到关注。对不同静力稳定性和深度的稳定层进行了模拟。描述重力流演化的两个重要参数是第一部分中定义的弗劳德数Fr和量μ=Co/Cgr，其中Co是无限小振幅长波在稳定层上传播的相速度，cgr是在没有稳定层时等效重力流的速度。我们确定了两个大的参数区域：当μ小于0.7时，重力流水头与支流分离，形成孤立型扰动，在此范围内，当μ较大时，可能形成第二个水头并破裂。
Abstract The two-dimensional numerical model for an atmospheric gravity current described in Part I is used to study the effect of an ambient low-level stable layer on the evolution of a gravity current. This is a common situation in the atmosphere, but appears to have received little attention in the literature. Simulations are presented for stable layers of various static stabilities and depths. Two important parameters characterizing the evolution of the gravity current are the Froude number Fr, defined in Part I, and the quantity μ=c o/c gr, where c o is the phase speed for the propagation of infinitesimal amplitude long waves on the stable layer and c gr, is the speed of the equivalent gravity current in the absence of the stable layer. We have identified two broad parameter regimes: when μ is less than about 0.7, the gravity current head separates from the feeder flow to form a solitary-type disturbance preceding the former and for the larger values of μ in this range, a second head may form and bre...