Harry Swinney | The University of Texas at Austin (original) (raw)
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Papers by Harry Swinney
Journal of Geophysical Research: Oceans, 2014
Physica D: Nonlinear Phenomena, 1991
Shock Wave Science and Technology Reference Library, 2007
ABSTRACT Shock waves form in air when a bullet or aircraft exceeds the speed of sound. In a granu... more ABSTRACT Shock waves form in air when a bullet or aircraft exceeds the speed of sound. In a granular medium, the sound speed is small (typically 10 cm/s), so shock waves form for ordinary rather than extreme conditions. Our group has examined oblique and normal shock waves in granular flow past a wedge(E.C. Rericha et al., Phys. Rev. Lett. 88, 025403 (2002).) and in vertically oscillated granular layers, (J. Bougie et al., Phys. Rev. E 66, 051301 (2002).) using laboratory experiments, molecular dynamics simulations, and simulations of continuum equations for granular flow. The flows we consider reach Mach numbers greater than ten, a regime that is difficult to study in gas flows. We find that the shocks formed in flows of particles in a vacuum exhibit properties similar to those of shocks in supersonic gases, but there are some differences that arise because of the inelastic collisions between particles in granular media. The molecular dynamics and continuum simulations are found to describe the observations well. Increasing the restitution coefficient toward unity (decreasing the dissipation toward zero) does not lead to any qualitative change in behavior.
... Session KH: Granular Flows IV. 5:15 PM6:59 PM, Monday, November 20, 2006. Tampa Marriott Wat... more ... Session KH: Granular Flows IV. 5:15 PM6:59 PM, Monday, November 20, 2006. Tampa Marriott Waterside Hotel and Marina Room: Florida Salon 6 Chair: Richard M. Lueptow, Northwestern University Abstract ID: BAPS.2006.DFD.KH.3. ...
ABSTRACT The jamming transition in granular media has been the subject of several studies in the ... more ABSTRACT The jamming transition in granular media has been the subject of several studies in the last years. However, an experimental observation of phase diagram of granular media in three dimensions is still lacking. The goal of this study is to obtain such a diagram as a function of the shear stress, the packing fraction, phi, and the pressure in a granular bed. Shear stress is obtained by measuring the force, F, needed to pull-up a paddle immersed in a granular bed as a function of its packing fraction and the depth of immersion. We find that the value of this force is strongly depending the packing fraction: for low packing fraction (phi
Journal of Geophysical Research: Oceans, 2014
Physica D: Nonlinear Phenomena, 1991
Shock Wave Science and Technology Reference Library, 2007
ABSTRACT Shock waves form in air when a bullet or aircraft exceeds the speed of sound. In a granu... more ABSTRACT Shock waves form in air when a bullet or aircraft exceeds the speed of sound. In a granular medium, the sound speed is small (typically 10 cm/s), so shock waves form for ordinary rather than extreme conditions. Our group has examined oblique and normal shock waves in granular flow past a wedge(E.C. Rericha et al., Phys. Rev. Lett. 88, 025403 (2002).) and in vertically oscillated granular layers, (J. Bougie et al., Phys. Rev. E 66, 051301 (2002).) using laboratory experiments, molecular dynamics simulations, and simulations of continuum equations for granular flow. The flows we consider reach Mach numbers greater than ten, a regime that is difficult to study in gas flows. We find that the shocks formed in flows of particles in a vacuum exhibit properties similar to those of shocks in supersonic gases, but there are some differences that arise because of the inelastic collisions between particles in granular media. The molecular dynamics and continuum simulations are found to describe the observations well. Increasing the restitution coefficient toward unity (decreasing the dissipation toward zero) does not lead to any qualitative change in behavior.
... Session KH: Granular Flows IV. 5:15 PM6:59 PM, Monday, November 20, 2006. Tampa Marriott Wat... more ... Session KH: Granular Flows IV. 5:15 PM6:59 PM, Monday, November 20, 2006. Tampa Marriott Waterside Hotel and Marina Room: Florida Salon 6 Chair: Richard M. Lueptow, Northwestern University Abstract ID: BAPS.2006.DFD.KH.3. ...
ABSTRACT The jamming transition in granular media has been the subject of several studies in the ... more ABSTRACT The jamming transition in granular media has been the subject of several studies in the last years. However, an experimental observation of phase diagram of granular media in three dimensions is still lacking. The goal of this study is to obtain such a diagram as a function of the shear stress, the packing fraction, phi, and the pressure in a granular bed. Shear stress is obtained by measuring the force, F, needed to pull-up a paddle immersed in a granular bed as a function of its packing fraction and the depth of immersion. We find that the value of this force is strongly depending the packing fraction: for low packing fraction (phi