Wed, 20 Aug 2008 22:07:19 BST CiteULike: dchen Aranson http://www.citeulike.org/user/dchen/author/Aranson CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2883395 <i>Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 5. (2007)</i><br /><br />Large-scale collective motion emerging in a monolayer of vertically vibrated elongated particles is studied. The motion is characterized by recurring swirls, with the characteristic scale exceeding several times the size of an individual particle. Our experiments identified a small horizontal component of the oscillatory acceleration of the vibrating plate in combination with orientation-dependent bottom friction (with respect to horizontal acceleration) as a source for the swirl formation. We developed a continuum model operating with the velocity field and local alignment tensor, which is in qualitative agreement with the experiment. Swirling motion in a system of vibrated elongated particles Igor Aranson Dmitri Volfson Lev Tsimring doi:10.1103/PhysRevE.75.051301 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 5. (2007) 2008-06-11T16:41:58-00:00 2007 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) 75 5 APS 2007 ellipsoid friction grains pre http://www.citeulike.org/user/dchen/article/2552556 <i>Physical Review Letters, Vol. 99, No. 15. (2007)</i><br /><br />Magnetic microparticles suspended on the liquid-air interface and subjected to an alternating magnetic field exhibit spontaneous formation of dynamic localized snake patterns. These patterns are accompanied by four large-scale hydrodynamic vortices located at the opposite ends of the snake patterns. We report detailed studies of these large-scale vortices and their relationship to the collective response of magnetic particles in the presence of an alternating magnetic field. We present a model based on the amplitude equation for surface waves coupled to the large-scale hydrodynamic mean flow equation. The model describes both the formation of the dynamic snake patterns and the induced structure of the experimentally observed hydrodynamic flows. Driven Magnetic Particles on a Fluid Surface: Pattern Assisted Surface Flows M Belkin A Snezhko IS Aranson WK Kwok doi:10.1103/PhysRevLett.99.158301 Physical Review Letters, Vol. 99, No. 15. (2007) 2008-03-18T19:26:14-00:00 2007 Physical Review Letters 99 15 APS 2007 surface