Nonlinear interactions between fluid flows inside and outside of sea ice

北极海冰是地球气候系统中最敏感的组成部分之一。它的重要性源于其相对较大的反射率，将大部分入射的短波辐射反射回太空，从而在地球的辐射预算中发挥重要作用。了解海冰的演变对于准确预测地球气候变化至关重要。与纯冰不同，海冰是一种反应性多孔介质，其中包含快速凝固过程中捕获的盐水袋。这种反应性多孔介质被称为糊状层。糊状层内外流体流动之间的相互作用决定了盐、动量和热量向糊状层-海洋界面的湍流输送。为了理解这些相互作用，需要研究在平均切变存在下，粘性层和底层海洋中浮力驱动的流动。海冰的动力学，和糊状层一般，迫使外部流仍然是一个开放的问题，在基本流体力学。它提供了一个丰富的数学系统来探索，对理解气候系统的一个关键方面具有重要意义。本项目的建议是开发新的分析和数值方法来解决这个问题。拟议的项目旨在将联合收割机直接数值模拟和数学理论相结合来研究这些相互作用。为此，将使用晶格玻尔兹曼（LB）和焓方法的组合。LBM是一个非常有效的工具，用于模拟随机流动，不断演变的几何形状，也易于并行化。模拟将用于提供这些相互作用的详细情况，模拟数据将用于开发简化的数学模型，用于将热量和盐从底层海洋转移到糊状层。

Arctic sea ice is one of the most sensitive components of the Earth's climate system. Its importance stems from its relatively large albedo that reflects a substantial portion of the incoming shortwave radiation back to space, thereby playing an important role in the Earth's radiation budget. Understanding the evolution of sea ice is critically important in accurately predicting changes in the Earth's climate.Unlike pure ice, sea ice is a reactive porous medium which contains pockets of brine which are trapped during rapid solidification. This reactive porous medium is referred to as a mushy layer. The interactions between fluid flows inside and outside of the mushy layer determine the turbulent transport of salt, momentum and heat to the mushy-layer-ocean interface. To understand these interactions, one needs to study the buoyancy driven flows in the mushylayer and the underlying ocean in the presence of mean shear. The dynamics of sea ice, and mushy layers generally, forced by an exterior flow remains an open problem in fundamental fluid mechanics. It presents a rich mathematical system to explore, with significant implications for understanding a key aspect of the climate system. The proposal of this project is to develop new analytical and numerical methods to address this problem.The proposed project aims to combine direct numerical simulations and mathematical theory to study these interactions. A combination of the Lattice Boltzmann (LB) and enthalpy methods will be used for this. The LBM is a highly effective tool for simulating flows over random, evolving geometries and is also amenable to easy parallelization. The simulations will be used to provide a detailed picture of these interactions, and the data from the simulations will be used to develop simplified mathematical models for the transport of heat and salt to the mushy layer from the underlying ocean.