pH-Sensitive Planar Laser-Induced Fluorescence Based Characterization Of Turbulent Mixing Induced By Fractal Oscillating Grids

This study examines passive scalar mixing in a tank stirred by fractal oscillating grids. Injection experiments are performed and pH-sensitive planar laser-induced fluorescence measurements are used to evaluate the influence of grid geometry on mixing time and local turbulent scalar behavior. Fractal grids are found to perform better than traditional Cartesian grids, with the I-Fractal configuration showing the highest efficiency. The mean flow generated by grid oscillations, generally more intense for fractal grids, has a major influence on the mixing mechanism, enhancing scalar patch transport toward the highly turbulent region swept by the grid. These results open the way for the development of efficient fractal oscillating grid mixers.