A numerical and analytical study of atmospheric undular bores
A numerical and analytical study of atmospheric undular bores
复制标题
大气波状钻孔的数值分析研究
DOI：
--
复制
发表时间：
1985
期刊：
影响因子：
--
通讯作者：
M. Miller
中科院分区：
文献类型：
--
作者：
N. A. Crook;M. Miller
本文借助于数值模式和理论分析，研究了大气起伏涌浪的形成和结构。数值模型首先被用来模拟异重流传播到一个不分层的环境。与现有理论的模型结果的详细比较表明，对于一个给定的压头的电流可以在一个更大的速度比无旋理论预测。当异重流传播到一个低水平的稳定层，它被发现，对于某些参数制度的波浪形孔的电流前面形成。两种不同类型的稳定层的结果进行了检查。对于位温呈阶梯分布的层，与经典的孔理论和两层流体密度流理论进行了比较，结果令人鼓舞地一致.当稳定层中位温呈线性分布时，可以得到能量守恒的解.数值场，然后与测量的牵牛花，在澳大利亚东北部观察到的波状孔，并再次协议是好的。最后，讨论了稳定层以上分层模式模拟的初步结果。
SUMMARY In this paper the formation and structure of an atmospheric undular bore is examined with the aid of a numerical model and theoretical analysis. The numerical model is first used to simulate a density current propagating into an unstratified environment. A detailed comparison of the model results with existing theory shows that for a given pressure head the current can travel at a greater speed than that predicted by irrotational theory. When the density current is allowed to propagate into a low-level stable layer it is found that for certain parameter regimes an undular bore forms ahead of the current. The results for two different types of stable layers are examined. For a layer with a step profile of potential temperature, comparison is made with both classical bore theory and the theory of density currents in two-layer fluids and encouraging agreement is found. When a linear profile is specified in the stable layer it is found that energy-conserving solutions can be obtained. The numerical fields are then compared with measurements of the morning glory, an undular bore observed in north-eastern Australia, and again agreement is good. Finally, preliminary results of model simulations with stratification above the stable layer are discussed.