We conducted visualization experiments to investigate the mixing of upper and lower stratified suspensions for macroscopic mixing. We used spectroscopy to distinguish the upper and lower suspensions in the images recorded by the color camera, by replacing the upper and lower suspended particles with blue and red fluorescent particles, respectively. We also proposed a method to determine the mass of adsorbed particles and the volume of fluorescent solution required to produce fluorescent particles by using the two calibration curves and the Freundlich equation. Visualization with fluorescent particles proved to be effective for macroscopic mixing by comparing mono and color images. Finally, we found good agreement in the trends between the experimental and numerical results.
