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RECORDATORIO: Seminario Extraodrinario ICF-UNAM 25/01/11, 12:30
RECORDATORIO:
Estimados colegas
(e-mail sin acentos)
HOY martes 25 de enero del 2011 tendremos un seminario extraordinario en
el Auditorio del ICF-UNAM a las 12:30 que sera impartido por el Dr. Andres
Santos del departamento de fisica de la Universidad de Extremadura, Espania
Titulo:
"Influence of particle roughness on some properties of granular gases"
Resumen:
The simplest model of a granular fluid consists of a system of identical,
inelastic smooth hard spheres with a constant coefficient of normal
restitution. Obviously, the model can be made closer to reality by introducing
extra ingredients. In particular, polydispersity and roughness are especially
relevant because they unveil an inherent breakdown of energy equipartition in
granular fluids, even in homogeneous and isotropic states. In this talk a fluid
mixture of inelastic rough hard spheres of arbitrary number densities, masses,
diameters, moments of inertia, and mutual coefficients of normal and tangential
restitution is considered.
In the first part of the talk, the collisional energy production rates
associated with the translational and rotational temperatures will be derived
by kinetic-theory arguments. The results will be applied to the homogeneous
free cooling of a binary mixture. The time evolution and steady values of the
three independent temperature ratios will be analyzed, with special emphasis on
the origin of an interesting paradox taking place in the quasi-smooth limit.
In the second part, the Boltzmann equation, which becomes very intricate when
it describes a granular gas made of inelastic and rough hard spheres, even in
the monodisperse case, will be replaced by a model kinetic equation that
preserves the main physical properties of the original description. The
resulting kinetic model will be applied to the paradigmatic uniform shear flow
state, finding that the reduced shear stress exhibits a non-monotonic
dependence on roughness that becomes less important as the inelasticity
increases.
===
Reciban cordiales saludos y espero verlos en el seminario
Dr. Remigio Cabrera-Trujillo
Instituto de Ciencias Fisicas,
Universidad Nacional Autonoma de Mexico
Cuernavaca AP 48-3, Morelos, Mexico 62210
Tel: (+52) 777 329 1757 (direct), (+52) 777 329 1745 (secretary)
http://www.fis.unam.mx/~trujillo