title: Levitation of heavy particles against gravity in asymptotically downward flows.
abstract: In the fluid transport of particles, it is generally expected that heavy particles carried by a laminar fluid flow moving downward will also move downward. We establish a theory to show, however, that particles can be dynamically levitated and lifted by interacting vortices in such flows, thereby moving against gravity and the asymptotic direction of the flow, even when they are orders of magnitude denser than the fluid. The particle levitation is rigorously demonstrated for potential flows and supported by simulations for viscous flows. We suggest that this counterintuitive effect has potential implications for the air-transport of water droplets and the lifting of sediments in water.
authors.affiliation: LUSAC, Université de Caen Basse-Normandie, Cherbourg, France.
authors.forename: Jean-Régis
authors.identifier: 0000000321337844
authors.initials: JR
authors.lastname: Angilella
authors.affiliation: Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Case
authors.affiliation: Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Adilson E
authors.identifier: 0000000317944828
authors.initials: AE
authors.lastname: Motter