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-   -   Visualize mixing (postprocessing) (https://www.cfd-online.com/Forums/cfx/26073-visualize-mixing-postprocessing.html)

Terje July 8, 2008 10:46

Visualize mixing (postprocessing)
 
Hi,

I want to model a micromixer where a "red" and a "blue" fluid are mixed. They both have water properties and start from the same inlet and I want to see how the interface between them evolves in a channel (disregarding diffusion).

This can be done by adding another variable which obeys the transportation equations. But when doing so there is quite a bit of numerical diffusion of the interface and the solver spends a lot of time. If, however, I run a simulation with just one phase the solution is quick. Since I have the streamlines these can be tracked back to the inlet to determine which phase is where.

Does anyone know a way to do this in postprocessing?

Thanks for your help!

- Terje

hjli6 July 8, 2008 12:10

Re: Visualize mixing (postprocessing)
 
Hi, Your case is one phase, it is two materials. You have to select Water volume Fraction for Variable in the postprocessing, the colour map can be selected as White to Blue. I did three kinds water flows. please see: http://e.simwe.com/attachments/2008/...2040520321.gif http://e.simwe.com/attachments/2008/...2040516521.gif

Terje July 9, 2008 04:21

Re: Visualize mixing (postprocessing)
 
Hi,

Thanks for your suggestion. I do not have access to the links you provided but I would very much like to see them. Could you change the access rights.

I am not sure if I understand your method. Does it involve having the volume fraction variable included in the simulation or is it only postprocessing.

Thanks again!

- Terje

hjli6 July 9, 2008 09:42

Re: Visualize mixing (postprocessing)
 
Hi,

The volume fraction variable is only select in postprocessing.

you may see this link:

http://e.simwe.com/10450/viewspace-7178

Terje July 9, 2008 12:40

Re: Visualize mixing (postprocessing)
 
Hi,

Nice videos! But I still do not understand how to track the volume fraction in post.

Could you please tell me in some detail what I need to do to e.g. to make a contour plot at the outlet of the volume fraction. Where the volume fraction is given at the inlet and the simulation is only one material.

Thanks!

- Terje


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