脉动压力脉动速度变形平均项的表达式  

Expressions for Pressure-Velocity-Gradient Correlations

作　　者：林多敏 蔡树棠[2] 

机构地区：[1]上海市应用数学和力学所 [2]中国科技大学

出　　处：《应用数学和力学》1991年第9期777-785,共9页Applied Mathematics and Mechanics

摘　　要：脉动压力脉动速度变形平均项,最初是Rotta改写压力梯度做功项得来的.但是,这项处理起来都很困难,从Rotta开始,以后Launder等人都对这项做过一些假定.本文根据脉动速度所满足的方程解出脉动压力,然后进而求出脉动压力乘上脉动速度变形的平均值,得到了脉动压力脉动速度变形平均项的完整表达式.这个表达式说明了Rotta和Launder等人的有限表达式是有一定道理的.本文所得的完整表达式分为两种情形加以讨论.一种是几种涡旋不分开的情形,另一种是三种涡旋分开考虑的情形.由此,本文为雷诺应力模式和三涡旋模式等湍流模式提供了完整的脉动压力脉动速度变形平均项的表达式.The term for pressure-velocity-gradient correlation was initiated by Rotta's[12] rewriting the correlation between the pressure fluctuation gradient and velocity fluctuation. However, it is very difficult to consider the effect of this term. Since Rotta's work,Launder et al. [7] has made some estimates of this term, in this paper, according to the equations for velocity fluctuation, the pressure fluctuation Is solved so that the average value of the product of the pressure fluctuation and the velocity fluctuation gradient is obtained. Thus, the whole expressions for the pressure-velocity-gradient correlation are derived. The result explains that the limited expressions by Rotta and Launder are reasonable to a certain degree. The whole expressions in this paper are discussed respectively in two situationsi one Is without a separate consideration of large and small vortexes, the other is with a separate consideration of three kinds of vortexes. Therefore, the paper gives the whole expressions for pressure-velocity-gradient correlation to the Reynolds stress turbulence model[7] and the three-vortex turbulence model.[13]

关 键 词：湍流模式 脉动压力 脉动速度变形 

分 类 号：O357.5[理学—流体力学]