Power law
The shear-rate dependence of the viscosity is denoted by a function F(g), where g is the shear-rate.
For the power law viscosity,
the function F(g) is written as follows :
F(g) = fac * (tnat*g)**(expo-1)
where fac is the viscosity
corresponding to a shear rate g = 1/tnat,
and expo is the power
law index.
Default values : fac = 1, tnat = 1, expo = 1
Selecting an option allows the user to modify the corresponding material parameter.
| -1 | Upper level menu |
| 1 | Modify fac = 1.0000000E+00 |
| 2 | Modify tnat = 1.0000000E+00 |
| 3 | Modify expo = 1.0000000E+00 |
A Picard iteration
is recommended instead of a full Newton iteration for cases where expo
< 0.7.
An evolution scheme
can also be used, starting from expo=1 (Newtonian fluid) and ending at
the desired value.
The units for g and
the parameters fac, tnat and expo are :
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