Index

Log - log law

Ver: 1
 
 

DESCRIPTION

For a generalized Newtonian fluid, the constitutive equation has the form

S = 2 * eta * D

where S is the extra-stress tensor, D is the rate of deformation tensor, and eta is the viscosity.

  The shear-rate dependence of the viscosity is denoted by a function F(g), where g is the shear-rate.

For the empirical log-log law, the function F(g) is written as follows :

F(g) = fac * 10**( a0 + a1 * log(g/gcrit) + a11 * log(g/gcrit)**2 )

By default, fac = 1, gcrit = 1 and a0 = a1 = a11 = 0.


OPTIONS

 
 -1   Upper level menu
  1   Modify  a0    = 0.0000000E+00
  2   Modify  a1    = 0.0000000E+00
  3   Modify  a11   = 0.0000000E+00
  4   Modify  fac   = 1.0000000E+00
5
   Modify  gcrit = 1.0000000E+00
NOTES In a non-isothermal flow problem, the 'Mixed dependence' for the temperature dependence of the viscosity
is mandatory when the 'Log-log' law is chosen.

The units for g and the parameters fac, gcrit, a0, a1 and a11 are :
 
 parameter 
mass
length
time
temperature
g, gcrit
-
-
-1
 -
fac
1
-1
-1
 -
a0, a1, a11
-
-
-
 -

SEE ALSO