Defocusing PTV applied to an open wet clutch

The optical measurement technique Defocusing Particle Tracking Velocimetry (Defocusing PTV) is applied to the sub-millimeter gap of an open wet clutch to gain deeper insights into the unknown flow, which causes a significant loss in nowadays automobiles. The present work improves the fundamental understanding of the flow and its contribution to the generated drag torque and the physical process of aeration. A set of governing analytical equations is revealed from in-depth theoretical considerations, which describe the general cause-effect relations of the flow. To gain deeper insights into the unknown intra-groove phenomena Defocusing PTV is successfully applied to (locally) extract precise vortex information and fine resolved wall shear stress values. Metrological insights are generated with the introduction of a new detection strategy and the proven flexibility of Defocusing PTV, which makes comprehensive magnification and location-accuracy studies possible. The work is completed with a flow analysis along the entire radial region of interest, and the consideration of a more complex groove geometry.