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Dispersed phase discretization - Mixture Model, Laminar Flow

Hi all,

I have a question related to the discretization of the dispersed phase in the Mixture Model, Laminar Flow interface. Under "Discretization" is only possible to choose the discretization for the fluid phase, while for the solid phase (i.e. phid) is not.

Do you know which discretization is used for the solid phase? Is it linear?

Any idea on why it is not possible to choose the discretization for the solid phase?

Thanks,

J

3 Replies Last Post Nov 14, 2012, 2:54 PM EST
Nagi Elabbasi Certified Consultant
Posted: 5 years ago Nov 13, 2012, 2:09 PM EST
In Mixture Model, Laminar Flow the discretization of phid (volume fraction of the dispersed phase) is I believe the same as the fluid velocity discretization.

Nagi Elabbasi
Veryst Engineering
In Mixture Model, Laminar Flow the discretization of phid (volume fraction of the dispersed phase) is I believe the same as the fluid velocity discretization. Nagi Elabbasi Veryst Engineering

Posted: 5 years ago Nov 13, 2012, 7:10 PM EST
Hi Nagi,

thanks for your reply. But I think that the discretization is linear (pressure and phid have the same amount of DoF). I just wonder why it is linear and why it is not possible to change it.

J
Hi Nagi, thanks for your reply. But I think that the discretization is linear (pressure and phid have the same amount of DoF). I just wonder why it is linear and why it is not possible to change it. J

Nagi Elabbasi Certified Consultant
Posted: 5 years ago Nov 14, 2012, 2:54 PM EST
Thanks J for pointing this out. Yes phid follows the discretization order of the pressure not the velocity. That selection results in a more diffusive yet more stable scheme. It would be nice to have the option in COMSOL to select an independent discretization order for phid. You can still do that now if you manually (and properly) couple two separate physics fields; single-phase laminar flow and transport of species.

Nagi Elabbasi
Veryst Engineering
Thanks J for pointing this out. Yes phid follows the discretization order of the pressure not the velocity. That selection results in a more diffusive yet more stable scheme. It would be nice to have the option in COMSOL to select an independent discretization order for phid. You can still do that now if you manually (and properly) couple two separate physics fields; single-phase laminar flow and transport of species. Nagi Elabbasi Veryst Engineering

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