分层流体中栅格湍流的特性

AN INVESTIGATION ON THE PROPERTIES OF GRID TURBULENCE IN STRATIFIED FLUID

本文考察了分层流体中栅格湍流衰减和演化过程的细节,通过对空间场的信息二维图象处理,获得了湍流动能、耗散率、功率谱及多种湍流尺度等主要湍流特征量。结果显示层结加速了湍流垂直动能的衰减,而水平动能的衰减几乎很少受影响。流场各特征量与前人结果也符合得较好。

The present experimental study investigates the properties and evolutions of grid turbulence in stratified fluid. By moans of computer image proccesing of particle streak pattern and relavent statistics, it is possible to obtain the flow structure details, turbulence decay of kinetic energy, various turbulent lengthscales, dissipation rate and spectrum. The experimental results further confirm the conclusion that the stratification of fluid mainly supre-sses the vertical turbulent velocity (increases its decay rate), and has little effect on evolution of the horizontal turbulent motion. Various turbulent scales obtained in the present experimental configuration and measurement method agree reasonably well with those in previous works.The present experimental study investigates the properties and evolutions of grid turbulence in stratified fluid. By moans of computer image proccesing of particle streak pattern and relavent statistics, it is possible to obtain the flow structure details, turbulence decay of kinetic energy, various turbulent lengthscales, dissipation rate and spectrum. The experimental results further confirm the conclusion that the stratification of fluid mainly supre-sses the vertical turbulent velocity (increases its decay rate), and has little effect on evolution of the horizontal turbulent motion. Various turbulent scales obtained in the present experimental configuration and measurement method agree reasonably well with those in previous works.