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Dispersed phase discretization - Mixture Model, Laminar Flow

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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 14 nov 2012, 14:54 GMT-5
Nagi Elabbasi Facebook Reality Labs

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Posted: 1 decade ago 13 nov 2012, 14:09 GMT-5
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

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Posted: 1 decade ago 13 nov 2012, 19:10 GMT-5
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 Facebook Reality Labs

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Posted: 1 decade ago 14 nov 2012, 14:54 GMT-5
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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