Publication Date

April 2010


Greg Voth




English (United States)


Gravitational granular collapse (GGC) occurs whenever a granular gas is allowed to evolve freely in gravity without the additional input of kinetic energy. The system dissipates its remaining energy through inelastic collisions as it settles into a granular solid at rest at the bottom of its enclosure in finite time. We are interested in the reasons for an observed divergence between experimental and theoretical results of the rate of decay. The use of realistic simulations confirms that, even in more closely ideal settings, the theory is not as universal as expected. We test the relative effects of a variety of system parameters on GGC dynamics and conclude that the second-power granular temperature decay law during GGC theoretically derived involves the somewhat unphysical approximation of particles that interact with a constant coefficient of resititution that is very far into the elastic limit.



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