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-   -   Turbulent flow of two incompressible fluids with the same physical properties (http://www.cfd-online.com/Forums/openfoam-solving/70959-turbulent-flow-two-incompressible-fluids-same-physical-properties.html)

ArneBab December 10, 2009 13:07

Turbulent flow of two incompressible fluids with the same physical properties
 
Hi,

Can OpenFOAM simulate the injection of two different incompressible fluids with the same physical properties (when it comes to fluid dynamics), including turbulent flow. Can it output the result in a way which allows me to visualize the fraction of the fluids at every point?

I've been testing OpenFOAM the last two days, but I didn't find a clear answer (neither here nor via Google).

I looked at the sloshingTank3D (interDyMFoam) and the elbow (icoFoam), as well as some others. What I couldn't answer for myself:

* Can I add injection of a specific fluid instead of setting a general velocity field?
* Can I "tag" a fluid, so I can identify it in ParaView?
* Does both work with turbulent flow?

(I currently evaluate different options for simulating contrast fluid in blood vessels)

mprinkey December 10, 2009 15:46

Quote:

Originally Posted by ArneBab (Post 239509)
Hi,

Can OpenFOAM simulate the injection of two different incompressible fluids with the same physical properties (when it comes to fluid dynamics), including turbulent flow. Can it output the result in a way which allows me to visualize the fraction of the fluids at every point?

I've been testing OpenFOAM the last two days, but I didn't find a clear answer (neither here nor via Google).

I looked at the sloshingTank3D (interDyMFoam) and the elbow (icoFoam), as well as some others. What I couldn't answer for myself:

* Can I add injection of a specific fluid instead of setting a general velocity field?
* Can I "tag" a fluid, so I can identify it in ParaView?
* Does both work with turbulent flow?

(I currently evaluate different options for simulating contrast fluid in blood vessels)

If the two fluids are hydrodynamically equivalent, there is no need to treat them as separate. Just use a passive scalar field as a marker and advect it using the normal phi in the convection terms. You can compute the effective diffusivity for the scalar based on the turbulent viscosity. Start with a transient, turbulent solver and add a passive scalar equation. It should go into the code after the PISO/pressure correction loop completes, so the flux field is conservative.

ArneBab December 11, 2009 05:32

Hi mprinkey,

Many thanks for your answer!

I now played a bit with a passive scalar field, and it seems to do exactly what I need.

Just to be sure I don't go into completely unrelated directions: Did I understand you correctly, that the next step now is to grab the source for a turbulent solver (for example turbFlow) and add the passive scalar equation (for example taken from the scalarTransportFoam)?

Best wishes,
Arne

ArneBab January 5, 2010 06:48

found
 
I now found the second answer myself - two weeks winter vacation and google helped -> yes, I have to build my own solver (turbulence + scalar field). And it doesn't seem horribly complicated - means I found a guide which shows the basics:

http://openfoamwiki.net/index.php/Ho...ure_to_icoFoam

Many thanks!


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