论文标题
地质湍流通过惯性 - 根治波扩散：流动时间依赖性的影响
Inertia-gravity-wave diffusion by geostrophic turbulence: the impact of flow time dependence
论文作者
论文摘要
湍流地质流动通过湍流的散射三维惯性波，导致其作用通过波形空间中的扩散过程重新分布。相应的扩散量张量由Kafiabad，Savva＆Vanneste（2019，J。FluidMech。，869，R7）在时间独立于时间独立的地质流动的假设下获得。我们放宽了这一假设，以研究波动在恒定频锥中的弱扩散如何是由于地质流动流的缓慢依赖性而产生的，从而影响波能的分布。我们发现，由单频波强迫产生的固定波能光谱位于恒定频锥周围的薄边界层中，其厚度由地球化流动的加速度频谱控制。我们获得了波能谱的显式分析公式，该公式与BousSinesQ方程的高分辨率模拟结果很好地吻合。
The scattering of three-dimensional inertia-gravity waves by a turbulent geostrophic flow leads to the redistribution of their action through what is approximately a diffusion process in wavevector space. The corresponding diffusivity tensor was obtained by Kafiabad, Savva & Vanneste (2019, J. Fluid Mech., 869, R7) under the assumption of a time-independent geostrophic flow. We relax this assumption to examine how the weak diffusion of wave action across constant-frequency cones that results from the slow time dependence of the geostrophic flow affects the distribution of wave energy. We find that the stationary wave-energy spectrum that arises from a single-frequency wave forcing is localised within a thin boundary layer around the constant-frequency cone, with a thickness controlled by the acceleration spectrum of the geostrophic flow. We obtain an explicit analytic formula for the wave-energy spectrum which shows good agreement with the results of a high-resolution simulation of the Boussinesq equations.
