平面湍性混合层流、射流四阶脉动速度关联的研究

本文用恒温热线风速仪和计算机采样及数据处理技术,结合 X 型探头的热线响应方程,对平面湍性混合层流、平面湍射流自模拟区内的四阶脉动速度关联量进行了测量;将所得的测量值与根据周培源教授提出的把四阶脉动速度关联用三个二阶脉动速度关联乘积的和来表示的假定而算得的相应值进行了比较,结果表明两者的吻合程度令人满意。说明在本文所述的剪切流场中,可通过简单而又有效的方法,求出四阶脉动速度关联值;在此基础上,可对三阶脉动速度关联方程进行封闭求解,提高对平均速度、雷诺应力等量的求解精度。

THE RESEARCH ON THE QUADRUPLE FLUCTUATING VELOCITY CORRELATIONS IN THE 2-D TURBULENT MIXING LAYER AND JET

The quadruple fluctuating velocity correlations in theself-preserving region of the 2-D turbulent mixing layer and jet aremeasured by using constant-temperature anemometer,hot-wire responseequations and data sampling technique.The measured results are com-pared with calculated results which are taken under the hypothesis,put forward by prof.Zhou Peiyuan,i.e.,quadruple fluctuating veloc-ity correlations are propotional to the sum of three product of doublefluctuating velocity correlations.The agreement between experimentaland calculated results is satisfactory.All of these show that the quad-ruple fluctuating velocity correlations in the shear flows mentionedin the paper can be got by a simple and effective method.Based ofthis,the equations of triple fluctuating velocity correlation becomeclosed and are to be solved,so more precise values of mean velocity,Reynolds stress and other quantities can be obtained by solving a seriesof equations.