The occurrence of system-scale coherent structures, so-called condensates, is a well-known phenomenon in two-dimensional turbulence. Here, the transition to condensate formation is investigated as a function of the magnitude of the force and for different types of forcing. Random forces with constant mean energy input lead to a supercritical transition, while forcing through a small-scale linear instability results in a subcritical transition with bistability and hysteresis. That is, the transition to condensate formation in two-dimensional turbulence is nonuniversal. For the supercritical case we quantify the effect of large-scale friction on the value of the critical exponent and the location of the critical point.

中文翻译：

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非普遍过渡到二维湍流

系统尺度相干结构的出现，即所谓的凝聚，是二维湍流中众所周知的现象。在这里，作为力的大小和不同类型的强迫的函数研究了向凝结水形成的转变。具有恒定平均能量输入的随机力导致超临界转变，而强制通过小尺度线性不稳定性导致具有双稳态和滞后的亚临界转变。也就是说，二维湍流中凝结水形成的转变是非普遍的。对于超临界情况，我们量化了大规模摩擦对临界指数值和临界点位置的影响。