[titio]

Hi all,

I am trying to model the flow of complex fluids in OpenFoam, in particular fluid where normal stresses can be significant. The constitutive equation that I am using, the PTT model, uses a convected derivative, in the form that can be seen in http://en.wikipedia.org/wiki/Upper_c...ime_derivative. That form of derivatives is much used in modelling viscoelastic flows.

I am having problems in representing it in terms of OpenFoam operators. Can anyone help me out. Sorry for not presenting the form of the derivative, but it is to much complex.

António

[kerstin]

Hi Antonio,
you need to include the tensor products in the PDE...
maybe this helps

http://www.cfd-online.com/OpenFOAM_D...es/1/6356.html

Kerstin