基于小波分析的表面活性剂减阻流体二维流场流动特性研究

Study on the characteristics of 2D CTAC solution flow by wavelets transform

该文采用粒子图像测速仪对矩形槽道内减阻流体二维流场进行测量,采用小波分析方法将流场分解为平均速度场与7个不同尺度的脉动场。结果显示减阻流体横向速度脉动几乎被完全抑制,流向速度脉动略低于水,但从波数为2开始小尺度脉动被明显削弱。减阻流体流向速度脉动呈条带分布,同流向基本平行,并且具有较大尺度,统计结果曲线也在相应位置出现局部大值,显示高脉动层存在的普遍性。

Particle image velocimetry （PIV） is used to measure the velocity of 2-D CTAC solution flow in the rectangular channel in this study. The mean streamwise velocity field and 7 fluctuation fields under different wave numbers are obtained by 1-D wavelets transform method in x direction. The results show that the fluctuations in drag-reducing fluid are lower than that in the water, especially in y direction. The fluctuations of streamwise velocity are decreased obviously with the increase of wave number starting from 2. Moreover, the region with high fluctuations of streamwise velocity is band-like and almost parallel to x direction. The streamwise velocity fluctuations are distributed within a range of low wave numbers. It is also astonished to find that a series of local maximal values appear in the profiles of RMS of streamwise velocity fluctuations which indicates the high fluctuation layers are ubiquitous in drag-reducing flow.