Hi, I am working with simpl
I am working with simpleFoam on polymer extrusion problem, using Bird-Carreau viscosity model. As is seen from source code, you used the velocity field (U) and the surface integration field (phi) to initialise the viscosity model:
My question is: how to add new factors into the viscosity model? For example, viscosity is also a function of pressure and temperature (called the WLF-Arrhenius equation).
If I want to implement this effect, I think I have to modify the sourcecode of transportModel and add pressure and/or temperature into the member functions. Can I have some guideline on the implementation? In addition, is the solution speed and convergence going to be affected seriously?
Thanks very much.
Create your own viscositymodel
Create your own viscositymodel and when you need your T look it up from the mesh (the mesh is also a database and holds all the fields on it)
const volScalarField& T = U_.mesh().lookupObject<volscalarfield>("T");
The solution speed should not be affected. Convergence only if there is a strong temperature dependence.
Hi, I've also started to
I've also started to implement a solver for polymerflow. Dissipation in that case is important - has anybody experience in adding this to the energy equation?
Hi Stefan, have a look here
have a look here:
I was wondering, how one can directly implement a new visosityLaw even as function of a Field like "T" inside the solver directly, and without going to call the predefined viscosityModels, without even to use them.
The problem is just to re-update each time the new viscosity at the new time step due to the new values of the Field "T" .
How this can be done ?
tell me if this example is true or not, where should be the update for varables?
the Example for the problem inside the solver:
if i am solving:
//My new viscosity law as function of field T
volScalaField new_nu = 2*T-5;
fvm::ddt(T) + fvm::div(phi, T) == fvm::laplacian(new_nu, T)
thanks a lot
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