A non-modal analytical method to predict turbulent properties applied to the Hasegawa-Wakatani model
A non-modal analytical method to predict turbulent properties applied to the Hasegawa-Wakatani model
复制标题
应用于长谷川-若谷模型的预测湍流特性的非模态分析方法
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
T. Carter
中科院分区：
文献类型：
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作者：
B. Friedman;T. Carter
线性本征模分析通常无法描述具有非正常线性算子和非正交本征模的模型系统中的湍流，这可能导致波动比本征模分析预期的更快地瞬时增长。当与能量守恒的非线性模式混合相结合时，即使在没有本征模不稳定性的情况下，瞬态增长也可以导致持续的湍流。由于线性算子最终提供了能量的湍流波动，它是有用的，以定义一个增长率，考虑到非模态效应，允许预测的能量注入，运输水平，甚至可能在亚临界状态下的湍流开始。我们定义这样一个非模态增长率使用一个相对简单的模型的统计效应，非线性对交叉相位和振幅比的系统状态变量。特别是，我们模拟的非线性三角函数一样，周期性的力量，随机化的状态变量每…
Linear eigenmode analysis often fails to describe turbulence in model systems that have non-normal linear operators and thus nonorthogonal eigenmodes, which can cause fluctuations to transiently grow faster than expected from eigenmode analysis. When combined with energetically conservative nonlinear mode mixing, transient growth can lead to sustained turbulence even in the absence of eigenmode instability. Since linear operators ultimately provide the turbulent fluctuations with energy, it is useful to define a growth rate that takes into account non-modal effects, allowing for prediction of energy injection, transport levels, and possibly even turbulent onset in the subcritical regime. We define such a non-modal growth rate using a relatively simple model of the statistical effect that the nonlinearities have on cross-phases and amplitude ratios of the system state variables. In particular, we model the nonlinearities as delta-function-like, periodic forces that randomize the state variables once every ...
影响因子：
6.3
作者：
Dudson, B. D.;Umansky, M. V.;Wilson, H. R.
通讯作者：
Wilson, H. R.