title: Quasi-static liquid-air drainage in narrow channels with variations in the gap.
abstract: This paper studies the shape of an air bubble quasi-statically flowing in the longitudinal direction of narrow channels. Two bottom topographies are treated, i.e., linear and quadratic variations of the gap along the transverse direction. This work analyses the main characteristics of the gas-liquid interface with respect to the wedge aspect ratio. From the convergence of asymptotic, numerical and experimental analyses, we found simple dependences for the finger width and total curvature as a function of channel aspect ratio. These results provide simple and general expressions for the pressure drop needed to overcome capillary forces and push the air finger inside the channel.
authors.affiliation: Institut de Mécanique des Fluides de Toulouse, UMR CNRS-INPT/UPS 5502, Av. du Professeur Camille Soula, 31400 Toulouse, France.
authors.forename: S
authors.initials: S
authors.lastname: Geoffroy
authors.forename: F
authors.initials: F
authors.lastname: Plouraboué
authors.forename: M
authors.initials: M
authors.lastname: Prat
authors.forename: O
authors.initials: O
authors.lastname: Amyot