CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (http://www.cfd-online.com/Forums/openfoam-solving/)
-   -   Unrealistic pressure drop in settlingFoam (http://www.cfd-online.com/Forums/openfoam-solving/96635-unrealistic-pressure-drop-settlingfoam.html)

jochemvandenbosch January 27, 2012 13:06

Unrealistic pressure drop in settlingFoam
 
1 Attachment(s)
Dear fellow OpenFOAM'ers,

As a part of my MSc thesis, I'm researching the pressure drop in dredging (sand/water) pipelines using settlingFoam. At the moment however I'm still simulating water flow.
I've tested my pipe mesh in simpleFoam & pisoFoam, both with excellent results regarding the pressure drop (+-5% with regards to the Moody chart). I'm simulating a straight smooth pipe of
D=0.15m
V=3m/s
rhoF=1000kg/m^3

Consequently I expect a pressure drop of approximately 400Pa/m
However settlingFoam yields: 210Pa/m whatever I try

To give you guys an idea what kind of mesh I'm using, I've attached my mesh.

Any ideas would be greatly appreciated!!!

Best regards,

ps. if anyone knows how to implement wall roughness in settlingFoam (without compiling a new solver), I'm listening!!!!!

jochemvandenbosch February 2, 2012 04:56

I discussed the issue with my professor. The pressure drop converges to the correct value if I increase the mesh. But due to the limited time/large size/limited computing power, I cannot adopt the mesh needed for a correct pressure drop.
Isn't there a wall model in settlingFoam??? I think there is not...

Could anyone verify if a wall model is missing in settlingFoam? If it's true is need to switch to another solver quickly!

Thanks in advance!


All times are GMT -4. The time now is 15:06.