论文标题
从纵向速度波动的零交叉点上估算湍流的积分长度尺度
Estimating the integral length scale on turbulent flows from the zero crossings of the longitudinal velocity fluctuation
论文作者
论文摘要
积分长度尺度（$ \ Mathcal {l} $）被认为是湍流最大动作的特征，因此，它是湍流理论和数值模拟的现代和经典方法中的输入参数。但是，在某些条件下，它的实验估计可能很困难，当很难实现测量$ \ Mathcal {l} $所需的实验校准（在大规模风能上进行热线动态测量和现场测量），或在“标准”设施中使用积极网格，由于其速度自动化的行为，该设施不在velocity Autocorelation $ crotter $ $ $ $ $ $上，以$ $ $ρ（r）。在这项工作中，我们提供了两种替代方法来估算$ \ MATHCAL {l} $，其中使用流速度波动的连续零交叉点之间的距离方差，从而降低了在类似的实验条件下估计$ \ Mathcal {l} $的不确定性。这些方法适用于各种情况，例如活动网格流，现场测量和大型风隧道。
The integral length scale ($\mathcal{L}$) is considered to be characteristic of the largest motions of a turbulent flow, and as such, it is an input parameter in modern and classical approaches of turbulence theory and numerical simulations. Its experimental estimation, however, could be difficult in certain conditions, for instance, when the experimental calibration required to measure $\mathcal{L}$ is hard to achieve (hot-wire anemometry on large scale wind-tunnels, and field measurements), or in 'standard' facilities using active grids due to the behaviour of their velocity autocorrelation function $ρ(r)$, which does not in general cross zero. In this work, we provide two alternative methods to estimate $\mathcal{L}$ using the variance of the distance between successive zero crossings of the streamwise velocity fluctuations, thereby reducing the uncertainty of estimating $\mathcal{L}$ under similar experimental conditions. These methods are applicable to variety of situations such as active grids flows, field measurements, and large scale wind tunnels.
