Superstructures and turbulent heat and momentum transport in inclined low-Prandtl-number convection

该项目致力于研究低普朗特数流体中倾斜湍流热对流中形成的上层结构的起源和动力学。这些上层建筑是跟随大规模流体循环的热羽流的集群。在该项目中，将开发或推进识别、提取和分析上层建筑几何和物理特性及其时间演化的算法。上层结构将从我们直接数值模拟产生的流场中提取出来。这里的重点将放在低普朗特数的流体上，比如液态金属，以及细长的对流单元，与没有任何单元倾斜的经典瑞利-贝纳德对流相比，在倾斜的热对流单元中，浮力和剪切的有利组合可以显著增强传热。特别地，我们将研究上层结构对系统中全局热量和动量输运的贡献，它们分别由努塞尔数和雷诺数表示。此外，还将研究瑞利数、普朗特数、对流单元长度比和倾角等控制参数对上部结构动力学的影响。最后，研究了局部热输运（努塞尔数）与上部结构的瞬时形式之间的关系。

The project is devoted to the investigation of the origin and dynamics of the superstructures that develop in inclined turbulent thermal convection in low Prandtl-number fluids. These superstructures are clusters of the thermal plumes that follow the large-scale circulation of the fluid. Within the project, algorithms to identify, extract and analyze the geometrical and physical properties of the superstructures and their temporal evolution are to be developed or advanced. The superstructures will be extracted from the flow fields that will be generated in our direct numerical simulations. The focus here will be on low Prandtl-number fluids, like in liquid metals, and on slender convection cells, where a favourable combination of buoyancy and shear in a tilted thermal convection cell can significantly enhance the heat transfer, compared to the classical Rayleigh-Benard convection without any cell tilt. In particular, we will investigate the contribution of the superstructures to the global heat and momentum transport in the system, which are expressed, respectively, by the Nusselt and Reynolds numbers. Furthermore, the influence on the superstructures dynamics of the control parameters, such as the Rayleigh number, Prandtl number, convection cell length ratios and the angle of inclination, will be studied. Finally, the relationship between the local heat transport (Nusselt number) and the instantaneous form of the superstructure will be investigated.