Ombroscopic imaging and PTV to reduce the depth of field in a flow with strong curvature effects

Abstract

The present work deals with the depth of field characterization in a complex flow with strong curvature effects: the bubbly Taylor Couette flow. Measurements were carried out in a 2D (axial and radial) plane with a large contribution of the azimuthal velocity on radial and axial velocity. Ombroscopic imaging technique coupled with a Particle Tracking Velocimetry have been used to accurately measure the depth of field in the working zone. We show that reducing this depth of field helps to minimize dispersed phase measurement errors in the radial direction for both position and velocity. We also found good agreement between results of the proposed method and the theoretical predictions of bubbles velocity in laminar Taylor-Couette flow.