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- Steven T Wereley, Richard M Lueptow
- 1998

The stability of supercritical Couette flow has been studied extensively, but few measurements of the velocity field of flow have been made. Particle image velocimetry (PIV) was used to measure the axial and radial velocities in a meridional plane for non-wavy and wavy Taylor–Couette flow in the annulus between a rotating inner cylinder and a fixed outer… (More)

- Antje Brucks, Tim Arndt, Julio M Ottino, Richard M Lueptow
- Physical review. E, Statistical, nonlinear, and…
- 2007

We consider the impact of the effective gravitational acceleration g{eff} on gravity-driven granular shear flow utilizing a tumbler of radius R rotating at angular velocity omega when g{eff} is varied up to 25 times the gravitational level on Earth in a large centrifuge. The Froude number Fr=omega{2}R/g{eff} is shown to be the proper scaling to characterize… (More)

- Nicholas A Pohlman, Benjamin L Severson, Julio M Ottino, Richard M Lueptow
- Physical review. E, Statistical, nonlinear, and…
- 2006

We investigate the effect of nanoscale variations in the surface roughness of individual particles on macroscale granular flow characteristics. Experiments were conducted in circular rotating tumblers with smooth and rough 2 and 3 mm steel particles. The smooth beads had a rms surface roughness of approximately 30 to 60 nm; rough beads had a surface… (More)

- Denis Martinand, Eric Serre, Richard M Lueptow
- 2009

Imposing axial flow in the annulus and/or radial flow through the cylindrical walls in a Taylor– Couette system alters the stability of the flow. Theoretical methods and numerical simulations were used to determine the impact of imposed axial and radial flows, homogeneous in the axial direction, on the first transition of Taylor–Couette flow in the… (More)

- Richard M Lueptow, Andreas Docter, Kyungyoon Min
- 1999

Flow between concentric cylinders with the inner cylinder rotating and an axial pressure gradient imposed in the annulus reveals a rich variety of flow regimes depending on the flow conditions. The occurrence of these flow regimes was studied experimentally by both visually and optically detecting the transition from one flow regime to another over a wide… (More)

- Steven T Wereley, Richard M Lueptow
- 1999

The flow in the gap between an inner rotating cylinder concentric with an outer stationary cylinder with an imposed pressure-driven axial flow was studied experimentally using particle image velocimetry ͑PIV͒ in a meridional plane of the annulus. The radius ratio was ϭ0.83 and the aspect ratio was ⌫ϭ47. Velocity vector fields for nonwavy toroidal and… (More)

- Steven T Wereley, Richard M Lueptow
- 1998

In rotating filtration, which is based on supercritical cylindrical Couette flow with a rotating porous inner cylinder, the motion of particles in the suspension depends on both centrifugal sedimentation and transport due to the vortical motion of Taylor vortices. We have simulated the motion of dilute, rigid, spherical particles in Taylor Couette flow… (More)

Rejection characteristics of organic and inorganic compounds were examined for six reverse osmosis (RO) membranes and two nanofiltration (NF) membranes that are commercially available. A batch stirred-cell was employed to determine the membrane flux and the solute rejection for solutions at various concentrations and different pH conditions. The results… (More)

- Olivier Czarny, Eric Serre, Patrick Bontoux, Richard M Lueptow
- 2003

The endwalls in a Taylor–Couette cell introduce adjacent boundary layers that interact with the centrifugal instability. We investigate the interaction between the endwall Ekman layers and the Taylor vortices near transition from nonvortical to vortical flow via direct numerical simulation using a spectral method. We consider a radius ratio of ϭ0.75 in a… (More)

- Alp Akonur, Richard M Lueptow
- 2003

The stability of wavy supercritical cylindrical Couette flow has been studied extensively, but few measurements of the velocity field in flow have been made. Particle image velocimetry was used to measure the azimuthal and radial velocities in latitudinal planes perpendicular to the axis of rotation for wavy cylindrical Couette flow in the annulus between a… (More)