In two-dimensional turbulent systems the redistribution of energy can be described by quadratic nonlinear three-wave interactions, which are limited by resonance conditions. The set of coupling modes can be understood as resonant manifold. It has been predicted by theory that, in the presence of a shear flow, the resonant manifold in wave-number space shrinks in time favoring large-scale structures. The phenomenon of manifold shrinking in the presence of shear flows is studied the first time experimentally in drift wave turbulence at the stellarator TJ-K by bicoherence analysis. By estimating effective mode numbers characterizing the width of the manifold, it is demonstrated that increasing shear leads to a shrinking of the resonance manifold.

中文翻译：

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区域流剪作用下共振歧管收缩的实验观察

在二维湍流系统中，能量的重新分布可以通过二次非线性三波相互作用来描述，而二次非线性三波相互作用受到共振条件的限制。耦合模式的集合可以理解为共振歧管。从理论上已经预测，在剪切流的存在下，波数空间中的共振流形会随时间缩小，从而有利于大型结构。通过双相干分析，首次在恒星TJ-K的漂移波湍流中，对存在剪切流的歧管收缩现象进行了实验研究。通过估计表征歧管宽度的有效模式数，可以证明，增加的剪切力会导致谐振歧管的收缩。