#### Filter Results:

- Full text PDF available (2)

#### Publication Year

1977

2009

- This year (0)
- Last 5 years (0)
- Last 10 years (6)

#### Publication Type

#### Co-author

#### Journals and Conferences

Learn More

- Ken Tore Tallakstad, Henning Arendt Knudsen, +4 authors Eirik Grude Flekkøy
- Physical review letters
- 2009

We study experimentally the case of steady-state simultaneous two-phase flow in a quasi-two-dimensional porous media. The dynamics is dominated by the interplay between a viscous pressure field from the wetting fluid and bubble transport of a less viscous, nonwetting phase. In contrast with more studied displacement front systems, steady-state flow is in… (More)

- Ken Tore Tallakstad, Grunde Løvoll, Henning Arendt Knudsen, Thomas Ramstad, Eirik Grude Flekkøy, Knut Jørgen Måløy
- Physical review. E, Statistical, nonlinear, and…
- 2009

We report on experimental studies of steady-state two-phase flow in a quasi-two-dimensional porous medium. The wetting and the nonwetting phases are injected simultaneously from alternating inlet points into a Hele-Shaw cell containing one layer of randomly distributed glass beads, initially saturated with wetting fluid. The high viscous wetting phase and… (More)

A fast screening method for the determination of the dissociation constants (pKa) of acidic, basic, and multivalent compounds was developed by using pressure-assisted capillary electrophoresis (PACE). External air pressure was applied to shorten the analysis time. The separation efficiency decreases as air pressure increases. However, it was found that air… (More)

- Thomas Ramstad, Alex Hansen, Pål-Eric Oren
- Physical review. E, Statistical, nonlinear, and…
- 2009

Using numerical simulations, we study immiscible two-phase flow in a pore network reconstructed from Berea sandstone under flow conditions that are statistically invariant under translation. Under such conditions, the flow is a state function which is not dependent on initial conditions. We find a second-order phase transition resembling the phase inversion… (More)

- Alex Hansen, G George Batrouni, Thomas Ramstad, Jean Schmittbuhl
- Physical review. E, Statistical, nonlinear, and…
- 2007

We study the scaling properties of the solid-on-solid front of the infinite cluster in two-dimensional gradient percolation. We show that such an object is self-affine with a Hurst exponent equal to 23 up to a cutoff length approximately g{-4/7}, where g is the gradient. Beyond this length scale, the front position has the character of uncorrelated noise.… (More)

- Thomas Ramstad, Alex Hansen
- Physical review. E, Statistical, nonlinear, and…
- 2006

We report numerical studies of the cluster development of two-phase flow in a steady-state environment of porous media. This is done by including biperiodic boundary conditions in a two-dimensional flow simulator. Initial transients of wetting and nonwetting phases that evolve before steady state has occurred, undergo a crossover where every initial pattern… (More)

- G G Batrouni, T Ramstad, A Hansen
- Philosophical transactions. Series A…
- 2004

We briefly review some important properties of superfluid flow, especially the problem of critical velocity. We then present new numerical simulation results for a mesoscopic model of superfluids shedding light on the free-energy landscape, the critical velocity and the formation of vortices, which destroy the superflow when the velocity is high.

- T Ramstad, T J Nestrick
- Bulletin of environmental contamination and…
- 1981

- Thomas Ramstad, Alex Hansen
- Physical review. E, Statistical, nonlinear, and…
- 2008

When immiscible wetting and nonwetting fluids move in parallel in a porous medium, an instability may occur at sufficiently high capillary numbers so that interfaces between the fluids initially held in place by the porous medium are mobilized. A boundary zone containing bubbles of both fluids evolves, which has a well-defined thickness. This zone moves at… (More)

We report on experimental and numerical studies of steady-state two-phase flow in a quasi twodimensional porous medium. Experimentally, the wetting and the non-wetting phase are injected simultaneously from alternating inlet points into a Hele-Shaw cell containing one layer of randomly distributed glass beads, initially saturated with wetting fluid.… (More)