title: Scaling at the selective withdrawal transition through a tube suspended above the fluid surface.
abstract: In the selective withdrawal experiment fluid is withdrawn through a tube with its tip suspended a distance S above an unperturbed two-fluid interface. At low withdrawal rates, Q, the interface forms a steady state hump and only the upper fluid is withdrawn. When Q is increased (or S decreased), the interface undergoes a transition so that the lower fluid is entrained with the upper one, forming a thin steady-state spout. Near this discontinuous transition the hump curvature becomes very large and displays power-law scaling behavior. This scaling is used to show that steady-state profiles for humps at different flow rates and tube heights can all be scaled onto a single similarity profile.
authors.affiliation: James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Itai
authors.initials: I
authors.lastname: Cohen
authors.forename: Sidney R
authors.initials: SR
authors.lastname: Nagel