论文标题
波浪强迫强迫的实验启发的分层湍流的数值研究
Numerical study of experimentally inspired stratified turbulence forced by waves
论文作者
论文摘要
通过伪triply-triply-priodic模拟研究了由内部波强迫的分层流，类似于在科奥利斯平台（Legi，Grenoble，France）\ Cite {savaro2020}中所获得的流量。通过惩罚方法模仿了由大振荡垂直面板组成的实验强迫机制。时间和时空光谱的分析表明，实验中最强强迫的流动由两个超塑的大型和准稳态的水平涡旋组成，内部波的内部波盒模式中的波浪和模式以外的波浪较弱。空间光谱和光谱能量预算确认，该流量处于非常小的水平弗洛德数字$ f_h $和浮力雷诺数$ r $接近Unity的中间状态。由于强迫频率$ω_f$的略小于Brunt-Väisälä频率$ n $，因此有能量转移向较慢的波浪和大涡流，这对应于水平上的高档能量通量。 研究了另外两个实验可行的参数集。 A larger amplitude forcing shows that it would indeed be possible to produce in huge apparatus like the Coriolis platform stratified turbulence forced by waves for small $F_h$ and buoyancy Reynolds number $R$ of order 10. Forcing slower waves for $ω_f = 0.40 N$ leaves space between $ω_f$ and $N$ for "down-time-scale" transfers through weakly nonlinear interactions with temporal spectra consistent带有$ω^{ - 2} $斜率。但是，对于这组参数，流量的较大尺度是强烈的耗散性的，并且没有降低的能量级联。
Stratified flows forced by internal waves similar to those obtained in the Coriolis platform (LEGI, Grenoble, France) \cite{Savaro2020} are studied by pseudospectral triply-periodic simulations. The experimental forcing mechanism consisting in large oscillating vertical panels is mimicked by a penalization method. The analysis of temporal and spatiotemporal spectra reveals that the flow for the strongest forcing in the experiments is composed of two superposed large and quasi-steady horizontal vortices, of internal waves in box modes and of much weaker waves outside the modes. Spatial spectra and spectral energy budget confirm that the flow is in an intermediate regime for very small horizontal Froude number $F_h$ and buoyancy Reynolds number $R$ close to unity. Since the forcing frequency $ω_f$ is just slightly smaller than the Brunt-Väisälä frequency $N$, there are energy transfers towards slower waves and large vortices, which correspond to an upscale energy flux over the horizontal. Two other experimentally feasible sets of parameters are investigated. A larger amplitude forcing shows that it would indeed be possible to produce in huge apparatus like the Coriolis platform stratified turbulence forced by waves for small $F_h$ and buoyancy Reynolds number $R$ of order 10. Forcing slower waves for $ω_f = 0.40 N$ leaves space between $ω_f$ and $N$ for "down-time-scale" transfers through weakly nonlinear interactions with temporal spectra consistent with $ω^{-2}$ slope. However, for this set of parameters, the large scales of the flow are strongly dissipative and there is no downscale energy cascade.
