CFD Online Discussion Forums - [OpenFOAM] Multiphase 3D free wave surface post-processing visualization in paraview

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- - [OpenFOAM] Multiphase 3D free wave surface post-processing visualization in paraview (https://www.cfd-online.com/Forums/paraview/106846-multiphase-3d-free-wave-surface-post-processing-visualization-paraview.html)

OK. If you have set interfaceCompression = 0 for (water oil) then it should NOT be a surprise when your "droplet" disintegrates upon hitting the other fluid. It will do so as an Eulerian mixture with a droplet size as prescribed in transportProperties. This is the same setup I have used for the image I posted. In this case, you want to clip everything by alphaair (which does have a sharp interface) to get just the liquid part and then color the liquid part by the dispersed phase fraction (alphaoil in my case).

As for sigma, it is inconsistent to apply a value for surface tension for a phase pair that does not have a VOF-like sharp interface (interfaceCompression = 0). Funny you have run into this because I just came across this issue myself. I have asked Henry to add a check for this in the solver so that a warning message tells you the value of sigma will be ignored when interfaceCompression = 0. In your case, just set sigma for (water oil) to 0. Incidentally, the way you have defined this value is wrong. For (air water) or (air oil) the value for sigma is the "surface tension"--which is 0.073 for water. For the liquid-liquid pair (water oil) it is the INTERFACIAL TENSION which has its own value depending on the phase pair and is NOT just a ratio of the surface tensions for the two liquids. For a typical water/oil pair this may be something in the range of 0.025. But as I said, you want to leave it as 0 if there is no sharp interface.
-Kent

Wave runup on cylinder

Hi all,

I am post processing wave runup on a cylinder. I have used t that contour filter to generate the free surface. But, would like to expose the fixed cylinder (strucutre3).

Any suggestion on how I may go about doing that?

Thank you.

Regards,
Prasad

Open a second instance of your controlDict, select only the patch(es) for the cylinder (not internal), and uncheck any fields. Then display this as a surface. You can change the color and opacity as well.

Thank you Kent. Now I am able to see the wave runup on the cylinder.

Alpha1 greater than 1

Hi, i'm pretty basic at CFD. Can anyone suggest me what could be the reason for alpha1 values being greater than 1. i would also appreciate if there exists any other methodology to trace where it is happening except finding it out in the time folder--> alpha file and locating the cell.

Quote:

Originally Posted by SirWombat (Post 381194)

easily done!

1. Make sure your have the "internalMesh" loaded from the "Mesh Parts"
2. Also select "alpha1" to load from the "Volume Fields"

Now use the "Threshold"-Filter with "alpha1".

Use 0.5 for the "Lower Threshold" and 1.5 for the "Upper Threshold"

(Although alpha should be in the range of 0 - 1 sometimes there are larger numbers than 1.)

You should get a resulting surface that you can even make semi transparent with the "opacity"-setting under the display-tab. And of course you can set it to show the velocity.

Greetings,
Jan

Hi David,

A simple question would like to ask:
How did you hide the front/side face in paraview?

Regards,
Yage

Hi Yage,
simply open up a new case (*.OpenFOAM file) or the external geometry (.stl or whatever), set solid color for it and in the properties panel, reduce Opacity (under styling) below 1.
Should work!