From wall modes to the boundary zonal flow in confined rotating thermal convection

由浮力和旋转驱动的湍流在自然界和技术中无处不在。在这个项目中，基于直接数值模拟（DNS），我们将研究旋转Rayleigh-Benard对流（RRBC）在不同的纵横比的圆柱形细胞的瑞利，普朗特，埃克曼，弗劳德数的广泛范围内，从线性壁模式的发病旋转热对流的地转制度，这是非常重要的，几乎所有的地球物理和天体物理系统。我们的研究将连接的线性壁模式状态，发生在散装对流的发病之前，与边界纬向流（BZF），它共存于湍流散装对流在地转制度。我们将研究全球流动结构的演变，作为对流开始时所有理论上可能的本征模的充分基础上的扩展。通过跟踪长度和时间尺度的演变，流动动力学的变化，以及系统中的热量和动量输运，我们将量化不同的流动特性并对其进行分析，最终将能够模拟和定量预测与壁模和BZF相关的漂移频率，典型长度和速度尺度以及热量输运，对于不同的Rayleigh，Prandtl，Ekman，弗劳德数阐明的热传输的贡献和对全球流动动力学的壁模式和BZF的影响是至关重要的了解在密闭容器中的实验室实验和地球物理和天体物理尺度上的RRBC的地转制度的属性。

Turbulent flows which are driven by buoyancy and rotation are omnipresent in nature and technology. In this project, based on direct numerical simulations (DNS), we will study rotating Rayleigh-Benard convection (RRBC) in cylindrical cells of different aspect ratios for a broad range of Rayleigh, Prandtl, Ekman, and Froude numbers, from the onset of the linear wall modes to the geostrophic regime of rotating thermal convection which is extremely important in almost all geophysical and astrophysical systems. Our study will connect the linear wall-mode states, which occur prior to the onset of bulk convection, with the boundary zonal flow (BZF), which coexists with turbulent bulk convection in the geostrophic regime. We will study the evolution of the global flow structure as an expansion on a full basis of all theoretically possible eigenmodes of the flow at the onset of convection. By tracking the evolution of the length and time scales, the change of the flow dynamics, and the heat and momentum transport in the system, we will quantify different flow characteristics and analyze them, and finally will be able to model and quantitatively predict the drift-frequency, typical length, and velocity scales and heat transport associated with the wall modes and the BZF, for different Rayleigh, Prandtl, Ekman, and Froude numbers. Elucidating the heat transport contributions and the effects on the global flow dynamics of the wall modes and of the BZFs is crucial for understanding the properties of the geostrophic regime of RRBC in confined containers in laboratory experiments and on the geophysical and astrophysical scales.