By specifying a list of coefficients in turbulenceProperties, e.g. for the
generalised Maxwell model:
modes
(
{
lambda 0.01;
}
{
lambda 0.04;
}
);
of for the generalised Giesekus model:
modes
(
{
lambda 0.01;
alphaG 0.05;
}
{
lambda 0.04;
alphaG 0.2;
}
);
Visco-elasticity stress tensors (sigma0, sigma1...) are solved for each mode and
summed to create the effective stress of the complex fluid:
Any number of modes can be specified and if only one mode is required the
'modes' entry is not read and the coefficients are obtained as before.
The mode sigma? fields are read if present otherwise are constructed and
initialised from the sigma field but all of the mode sigma? fields are written
for restart and the sigma field contains the sum.
References:
http://en.wikipedia.org/wiki/Generalized_Maxwell_model
Wiechert, E. (1889). Ueber elastische Nachwirkung.
(Doctoral dissertation, Hartungsche buchdr.).
Wiechert, E. (1893).
Gesetze der elastischen Nachwirkung für constante Temperatur.
Annalen der Physik, 286(11), 546-570.
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