Linear damping is widely applied in experiments and fluid models to describe the large-scale dissipation that absorbs upscale energy transfers in two-dimensional (2D) turbulence. However, in many systems, it is not justified that linear damping is a good model and it is hard to obtain the damping coefficient from directly measurable quantities. Based on the forcing-scale resolving structure-function theory of homogeneous isotropic 2D turbulence derived by (J. Fluid Mech. 2018, vol. 851, pp. 672–686.), we propose a procedure that simultaneously obtains the magnitude of energy flux, the energy injection scale and the damping coefficient by fitting the measurable second- and third-order velocity structure functions. Also, a test function based on the structure-function theory is proposed to justify the form of linear damping on each scale. The validity of this procedure is tested against data obtained from numerical simulations.

中文翻译：

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量化二维湍流中的线性阻尼

线性阻尼在实验和流体模型中被广泛应用，以描述吸收二维（2D）湍流中高档能量传递的大规模耗散。但是，在许多系统中，线性阻尼不是一个好的模型是不合理的，并且很难从直接可测量的量中获得阻尼系数。基于（J. Fluid Mech。2018，vol.851，pp.672-686。）推导的均质各向同性二维湍流的强迫尺度解析结构函数理论，我们提出了同时获得能量通量大小的程序，通过拟合可测量的二阶和三阶速度结构函数，确定能量注入比例和阻尼系数。此外，提出了一种基于结构函数理论的测试函数，以证明每种尺度上线性阻尼的形式是合理的。