title: Simulation of granular jets: is granular flow really a perfect fluid?
abstract: We perform three-dimensional simulations of the impact of a granular jet for both frictional and frictionless grains. Small shear stress observed in the experiment [X. Cheng et al., Phys. Rev. Lett. 99, 188001 (2007)] is reproduced through our simulation. However, the fluid state after the impact is far from a perfect fluid, and thus the similarity between granular jets and quark gluon plasma is superficial because the observed viscosity is finite and its value is consistent with the prediction of the kinetic theory.
authors.affiliation: Yukawa Institute for Theoretical Physics, Kyoto University Kitashirakawa Oiwakecho, Kyoto 606-8502 Japan.
authors.forename: Tomohiko G
authors.initials: TG
authors.lastname: Sano
authors.forename: Hisao
authors.initials: H
authors.lastname: Hayakawa