Investigation of Fluid Flow Out of a Microcavity Using PIV

This article presents the results of an experimental and corresponding analytical investigation of fluid flow out of a shallow microcavity (dimple) due to surface shear. An experimental test rig was designed, developed, and used to demonstrate shear-driven fluid flow out of a microcavity. The experimental test rig consists of a flat steel belt driven against a microcavity filled with a fluid. Microparticle image velocimetry ( PIV) was employed to visualize the shear-driven cavity flow and generate the streamline contours of the flow field. Two different sets of experiments were conducted. The first set examines the important factors that affect the flow field, and these include the cavity depth-to-width ratio (aspect ratio) and the speed of the flat belt. The second set of experiments was designed to observe the important fluid flow phenomena including the extraction and stagnation of the fluid above and below a critical cavity depth. A model was also developed using the computational fluid dynamic software COMSOL Multiphysics (1) to corroborate the experimental and analytical results. The results are in good agreement.