rhoCentralDyMFoam for subsonic flows

polo · December 1, 2015, 03:59

Dear all,

make it sense to use rhoCentralFoam oder rhoCentralDyMFoam for subsonic flows? So maybe for an axial fan were the maximum speed of the fan is 40 m/s so Ma No. < 0.12.

Or must I used pressure-based rhoPimpleDyMFoam for such low Mach number flows?

Thanks and Regards

mkraposhin · December 1, 2015, 04:12

Hi,

rescently we made hybrid Central/PISO solver which mixes schemes from rhoCentralFoam and rhoPimpleFoam. If you are interested, you can download it here
https://github.com/unicfdlab/pisoCentralFoam
and test

polo · December 1, 2015, 04:36

Hey Matevey,

many thanks for you very fast reply! I have download your solver and will test it. Currently I read your paper.

My stupid question would be ... can I do something (physically) wrong, if I use rhoCentralFoam or rhoCentralDyMFoam for low Machnumber flows? if yes, can you shortly explain what?

Regards

mkraposhin · December 1, 2015, 04:46

Quote:

Originally Posted by polo

can I do something (physically) wrong, if I use rhoCentralFoam or rhoCentralDyMFoam for low Machnumber flows? if yes, can you shortly explain what?

Regards

rhoCentralFoam implements Kurganov-Tadmore scheme, which was derive for solving hyperbolic equations, but with low Mach number equations becomes elliptic, so this scheme becames invalid for incompressible flows.

Also, KT scheme is explicit and it limits timestep with the Acoustic Courant number. So, if your local speed of flow is much smaller then sonic speed, this will lead to very smal time steps

Here you can find examples of using hybrid scheme for compressor simulation:
https://github.com/unicfdlab/realLifeExamples

polo · December 1, 2015, 06:29

thank you very much ... I will have a deeper look in your great work... http://www.cfd-online.com/Forums/ope...ntralfoam.html

compilation in OpenFOAM 2.3.0 works without any errors ;-)

December 1, 2015, 03:59	rhoCentralDyMFoam for subsonic flows	#1
polo New Member Join Date: Jul 2012 Posts: 7 Rep Power: 13	Dear all, make it sense to use rhoCentralFoam oder rhoCentralDyMFoam for subsonic flows? So maybe for an axial fan were the maximum speed of the fan is 40 m/s so Ma No. < 0.12. Or must I used pressure-based rhoPimpleDyMFoam for such low Mach number flows? Thanks and Regards

December 1, 2015, 04:12		#2
mkraposhin Senior Member Matvey Kraposhin Join Date: Mar 2009 Location: Moscow, Russian Federation Posts: 355 Rep Power: 21	Hi, rescently we made hybrid Central/PISO solver which mixes schemes from rhoCentralFoam and rhoPimpleFoam. If you are interested, you can download it here https://github.com/unicfdlab/pisoCentralFoam and test __________________ MDPI Fluids (Q2) special issue for OSS software: https://www.mdpi.com/journal/fluids/..._modelling_OSS GitHub: https://github.com/unicfdlab Linkedin: https://linkedin.com/in/matvey-kraposhin-413869163 RG: https://www.researchgate.net/profile/Matvey_Kraposhin

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December 1, 2015, 04:36		#3
polo New Member Join Date: Jul 2012 Posts: 7 Rep Power: 13	Hey Matevey, many thanks for you very fast reply! I have download your solver and will test it. Currently I read your paper. My stupid question would be ... can I do something (physically) wrong, if I use rhoCentralFoam or rhoCentralDyMFoam for low Machnumber flows? if yes, can you shortly explain what? Regards

December 1, 2015, 06:29		#5
polo New Member Join Date: Jul 2012 Posts: 7 Rep Power: 13	thank you very much ... I will have a deeper look in your great work... http://www.cfd-online.com/Forums/ope...ntralfoam.html compilation in OpenFOAM 2.3.0 works without any errors ;-)