Helical Turbulence Prevails over Inertial Waves in Forced Rotating Flows at High Reynolds and Low Rossby Numbers
Helical Turbulence Prevails over Inertial Waves in Forced Rotating Flows at High Reynolds and Low Rossby Numbers
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DOI：
10.1175/2010jas3445.1
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发表时间：
2011-11-01
影响因子：
3.1
通讯作者：
Pouquet, A.
中科院分区：
文献类型：
--
作者：
Baerenzung, Julien;Rosenberg, D.;Pouquet, A.
本文研究了固体自转至雷诺数Re类似于1×10(5)和Rossby数Ro类似于3×10(-3)时螺旋湍流的光谱规律。强迫函数是一种完全螺旋流，也可以被视为模拟大气对流运动的效果。Baerenzung等人以前开发的模型的变体。它的效率也与Chollet和Lesieur的谱大涡模拟(LES)以及欠分辨的大涡模拟(DNS)进行了对比。包含螺旋度对谱涡耗散和涡噪声贡献的模型表现最好，允许恢复流动的统计特征。即使该模型是基于各向同性假设的，作者在先前的研究中证明，在所考虑的参数范围内，中等Rossby数的小尺度流动可以被认为是各向同性的，因此他们的模型适合于处理这类流动。在固定的雷诺数下，降低Rossby数会导致波导型惯性螺旋度的级联到小尺度。然而，在固定的Rossby数下，增加雷诺数将导致系统被湍流能量交换所主导，其中惯性波的作用是在加强大尺度的同时削弱直接的能量级联。发现一个有用的数据划分参数为N-C=ReRo=U-Rms(2)/[nu Omega]，其中U-RMS、nu和Omega分别为均方根速度、粘度和转速。决定能量级联是正向还是反向的参数--在这种情况下，小尺度的级联主要是螺旋度的级联--与Ro有关。
A study of spectral laws for helical turbulence in the presence of solid body rotation up to Reynolds numbers Re similar to 1 x 10(5) and down to Rossby numbers Ro similar to 3 X 10(-3) is presented. The forcing function is a fully helical flow that can also be viewed as mimicking the effect of atmospheric convective motions. Variants of a model developed previously by Baerenzung et al. are tested in the helical case against direct numerical simulation (DNS), using data from a run on a grid of 1536(3) points; its efficiency is also contrasted against a spectral large-eddy simulation (LES) by Chollet and Lesieur, as well as an underresolved DNS. The model including the contribution of helicity to the spectral eddy dissipation and eddy noise behaves best, allowing the recovery of statistical features of the flow. Even if the model is based on isotropic assumptions, the authors demonstrated in a previous study that the small scales of flows at moderate Rossby number can be considered to be isotropic in the range of parameters considered here and that therefore their model is appropriate to treat this kind of flow.An exploration of parameter space is then performed beyond what is feasible today using DNS. At a fixed Reynolds number, lowering the Rossby number leads to a regime of wave-mediated inertial helicity cascades to small scales. However, at a fixed Rossby number, increasing the Reynolds number leads the system to be dominated by turbulent energy exchanges where the role of inertial waves is to weaken the direct cascade of energy while strengthening the large scales. It is found that a useful parameter for partitioning the data is N-C = ReRo = U-rms(2)/[nu Omega], with U-rms, nu, and Omega being the rms velocity, the viscosity, and the rotation rate, respectively. The parameter that determines how much the energy cascade is direct or inverse-in which case the cascade to small scales is predominantly that of helicity-is linked to Ro.