In my case, I am using particles that are almost 8 times higher than the fluid. A stirrer is used for the rotation of the suspension. A circular cylindrical substrate is dipped into the suspension. When I withdraw the substrate from the suspension, I found a huge number of particles over the substrate. If we follow the streamlines theory of fluid mechanics, a small number of particles should be over the substrate. I believe some forces help the particles to move near the substrate. I need some explanation on this phenomenon.