Reduced models for wave-balanced flow interactions

二维平衡流中内波能量频谱扩散

Frequency spreading of internal wave energy by balanced flows in two dimensions

研究二维平衡流中内波能量频谱扩散机制，发现真实湍流流场中频谱扩散弱于合成流场，推导出频谱扩散时间尺度，揭示大气和海洋中宽带频谱的其他成因。

Nonlinear energy transfers and phase diagrams for geostrophically balanced rotating--stratified flows

Equilibrium statistical mechanics tools have been developed to obtain indications about the natural tendencies of nonlinear energy transfers in two-dimensional and quasi two-dimensional flows like rotating and stratified flows in geostrophic balance. In this article, we consider a simple model of such flows with a non-trivial vertical structure, namely two-layer quasi-geostrophic flows, which remain amenable to analytical study. We obtain the statistical equilibria of the system in the case of a linear vorticity-stream function relation, build the corresponding phase diagram, and discuss the m…

Point vortex dynamics in three-dimensional ageostrophic balanced flows

Geophysical turbulent flows, characterized by rapid rotation, quantified by small Rossby number, and stable stratification, often self-organize into a collection of coherent vortices, referred to as a vortex gas. The lowest order asymptotic expansion in Rossby number is quasigeostrophy which has purely horizontal velocities and cyclone-anticylone antisymmetry. Ageostrophic effects are important components of many geophysical flows and, as such, these phenomena are not well-modeled by quasigeostrophy. The next order correction in Rossby number, which includes ageostrohpic affects, is so-called …

Well-balanced and flexible morphological modeling of swash hydrodynamics and sediment transport

Existing numerical models of the swash zone are relatively inflexible in dealing with sediment transport due to a high dependence of the deployed numerical schemes on empirical sediment transport relations. Moreover, these models are usually not well-balanced, meaning they are unable to correctly simulate quiescent flow. Here a well-balanced and flexible morphological model for the swash zone is presented. The nonlinear shallow water equations and the Exner equation are discretized by the shock-capturing finite volume method, in which the numerical flux and the bed slope source term are estima…

下一阶平衡模型捕捉亚中尺度物理与统计特征

Next-order balanced model captures submesoscale physics and statistics

本文通过非线性模拟证明基于位涡的下一阶Rossby平衡模型QG+1能捕捉海洋亚中尺度物理特征，包括气旋尾部、非地转锋面及锋生爆破，且反演简单，是研究上层海洋亚中尺度动力学的有效工具。

表面重力波与空间尺度相当的平均流相互作用。第一部分：约化波动方程

Surface gravity wave-mean flow interaction with comparable spatial scales. Part I: reduced wave equations

针对空间尺度与波长相当的背景流上的表面重力波，提出等价可解性条件方法，将3D问题约化为2D方程，并推导出窄带波的薛定谔方程形式，消除了快速波周期的时间分辨负担。