论文标题
冷却对流层渗透到稳定分层的成分梯度中：低prandtl数字的夹带
Penetration of a cooling convective layer into a stably-stratified composition gradient: entrainment at low Prandtl number
论文作者
论文摘要
当从上方冷却具有组成梯度的稳定分离的流体时，我们研究了对流层的形成和演变。我们使用bousinessq近似值进行一系列2D模拟，prandtl数量从PR = 0.1到7，将先前的盐水上的工作扩展到低PR。我们表明，对流区的演变由夹带处方很好地描述，其中使用的对流运动的动能的固定部分用于将界面处的流体与稳定层混合。我们测量夹带效率，并发现它随着prandtl数量的减少或增加的热通量而生长。确定夹带率的动能通量是总对流光度的一小部分。在这种时间依赖的情况下，界面处的密度比被驱动到狭窄范围，取决于PR的值，并且具有足够低的值以占主导地位的界面传输。我们表征了界面通量比及其如何取决于界面稳定性。我们提出了一个分析模型，该模型用两个参数（夹带效率和界面热传输）来解释对流层的增长，这两者都可以从模拟中进行测量。
We study the formation and evolution of a convective layer when a stably-stratified fluid with a composition gradient is cooled from above. We perform a series of 2D simulations using the Bousinessq approximation with Prandtl number ranging from Pr = 0.1 to 7, extending previous work on salty water to low Pr. We show that the evolution of the convection zone is well-described by an entrainment prescription in which a fixed fraction of the kinetic energy of convective motions is used to mix fluid at the interface with the stable layer. We measure the entrainment efficiency and find that it grows with decreasing Prandtl number or increased applied heat flux. The kinetic energy flux that determines the entrainment rate is a small fraction of the total convective luminosity. In this time-dependent situation, the density ratio at the interface is driven to a narrow range that depends on the value of Pr, and with low enough values that advection dominates the interfacial transport. We characterize the interfacial flux ratio and how it depends on the interface stability. We present an analytic model that accounts for the growth of the convective layer with two parameters, the entrainment efficiency and the interfacial heat transport, both of which can be measure from the simulations.
