interpreting velocity field

asharma · October 8, 2010, 01:23

Hi,
I've recently started using Openfoam, i'm planning to club my flow field results with Lagrangian particle dispersion model that i have coded. I'm having trouble interpreting the velocity data, for example in the example "cavity" run with RAS, for time step 20 we get a listing of 400 velocity data points. I understand my mesh is 20*20*1 grid , and velocities are calculated at volume centers. What co-ordinates do the results pertain to, or other wise is it possible to get velocity field in terms of exact gird location in my mesh.

Hope i'm clear with what i'm trying to get at...

thanks in advance!

abhinav

santiagomarquezd · October 8, 2010, 20:21

Abhinav, values are calculated at cell centres, but this info is not stored in /constant/polyMesh structure, so to obtain the coordinates of points which solution belongs to you have the command,

writeCellCentres

this command will give you three files in /0

ccx
ccy
ccz

they have the x, y and z coordinates of cell centres for internal mesh and face centres for boundary mesh.

Regards.

asharma · October 9, 2010, 01:19

Thank you so much Santiago, ill be back with more queries soon!...

regards,
Abhinav

October 8, 2010, 01:23	interpreting velocity field	#1
asharma New Member Abhinav Sharma Join Date: Sep 2010 Posts: 28 Rep Power: 15	Hi, I've recently started using Openfoam, i'm planning to club my flow field results with Lagrangian particle dispersion model that i have coded. I'm having trouble interpreting the velocity data, for example in the example "cavity" run with RAS, for time step 20 we get a listing of 400 velocity data points. I understand my mesh is 20201 grid , and velocities are calculated at volume centers. What co-ordinates do the results pertain to, or other wise is it possible to get velocity field in terms of exact gird location in my mesh. Hope i'm clear with what i'm trying to get at... thanks in advance! abhinav

October 8, 2010, 20:21		#2
santiagomarquezd Senior Member Santiago Marquez Damian Join Date: Aug 2009 Location: Santa Fe, Santa Fe, Argentina Posts: 452 Rep Power: 23	Abhinav, values are calculated at cell centres, but this info is not stored in /constant/polyMesh structure, so to obtain the coordinates of points which solution belongs to you have the command, writeCellCentres this command will give you three files in /0 ccx ccy ccz they have the x, y and z coordinates of cell centres for internal mesh and face centres for boundary mesh. Regards. beeo and liyijun like this. __________________ Santiago MÁRQUEZ DAMIÁN, Ph.D. Research Scientist Research Center for Computational Methods (CIMEC) - CONICET/UNL Tel: 54-342-4511594 Int. 7032 Colectora Ruta Nac. 168 / Paraje El Pozo (3000) Santa Fe - Argentina. http://www.cimec.org.ar

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October 9, 2010, 01:19		#3
asharma New Member Abhinav Sharma Join Date: Sep 2010 Posts: 28 Rep Power: 15	Thank you so much Santiago, ill be back with more queries soon!... regards, Abhinav