Fig. 12: The shear viscosity-to-entropy density ratio (in units of 1/4π ) for various media (from the talk by Cs ¨org ˝o).
Theory Summary: International Symposium on Multiparticle Dynamics 2008
Pr the radial pressure, P⊥ the tangential pressure, qα the heat ﬂux, ǫ the energy density of the null ﬂuid describing dissipation in the free streaming approximation, η the shear viscosity coeﬃcient, V α the four velocity of the ﬂuid, χα a unit four vector along the radial direction and lα a radial null four vector.
Relativistic Fluids and the Physics of Gravitational Collapse
For a l = m = 2 axial mode the instability’s growth rate scales as (ΩqR3/M )10 (in geometrical units, where ΩqR3/M ≪ 1) while the damping rate due to shear viscosity is independent of Ω.
Matters of Gravity, the newsletter of the APS TG on gravitation
Knowing Knudsen While each transport coeﬃcient provides insight into the medium, the ratio of shear viscosity η to entropy density s has attracted far and away the most attention, in very large part due to the bold conjecture that this ratio satisﬁes a “quant um bound ” η/ s ≥ 1/4π (in natural units).
Puzzles, Progress, Prospects: pre-Summary for the Quark Matter 2009 Conference
In Fluid Mechanics the constitutive equation relates the stress on a ﬂuid element to other ﬂuid quantities by the relation T = −pI + S , where T is the Cauchy stress tensor, p stands for the pressure, I is the unit tensor, µ is the dynamic viscosity and S is the deviatoric part of the stress tensor.
Existence for the steady problem of a mixture of two power-law fluids