圆柱热尾流中温度的概率密度函数

摘要

本文通过实验研究圆柱热尾流中温度的概率密度函数在不同雷诺数下沿中心线的演变以及其与湍流混合程度的关系.实验中雷诺数的取值范围是1200-8600,温度是由直径为0.63 μm的冷线探针测量的.实验结果表明,温度概率密度函数在尾流中场区随空间位置变化显著.雷诺数的增加加快了这个变化过程,特别加速了尾流中心线温度的概率密度函数从非高斯向近似高斯分布的演变.%In this article, we report on an experimental research on the probability density function (PDF) of temperature measured in the wake of a circular cylinder slightly heated and its relationships with the turbulent mixedness under different Reynolds numbers (1200-8600). The temperature is measured by a probe of cold-wire with 0.63-μm in diameter. Results show that the temperature PDF varies significantly with location in the wake. An increase in Reynolds number speeds up this variation, particularly accelerates the evolution from totally non-Gaussianity to near-Gaussianity along the wake centreline.