OPEN_FOAM for and idiot?

M_RED · May 14, 2014, 13:14

Hello Everyone,

First, my background in CFD is decent, but with expensive commercial software, i.e. Ricardo Vectis, AVL FIre, and Fluent for Catia. I know what I want to get out of the simulation, I just have no idea about anything at all on OPENfoam

Now, I am finding myself in a situation where i need to do some preliminary / first past sort of simulation on some ducting to evaluate if changes are OK. Basically, I have a duct, it enters a plenum and 5-7 ducts exit, each with a restrictor/throttling plate. I have a current design, and a crappy previous work .pdf, that shows volume flow rate is balanced and basic acceptable level of pressure drop. Everything is steady state.

I want to be able to change the plenum, and tweak it until I show the same mass flow rate, and pressure drop.

I have looked through the Wikis and opensource stuff, but it seems the windows based one are lacking something. (like ease of use..) or aren't actually free.

Can anyone recommend a set of programs, one that are actually free to use, and two let me do the basic pre-processing, i.e. meshing from an igs file, and setting up b/c's, and something to actually post-process too. (I think paraview may have that one covered?)

Am I silly to think meshing and set up is the same GUI?

Also, crap, I can't edit the title.... Oh the irony...

chegdan · May 14, 2014, 15:21

James,

Welcome! First off, your title actually caught my attention so I call that a win if you can get traffic on your posts. Secondly, this level of frustration and "what do I do next?" is a coherent state that most all of us have reached at some point

Now, here are some thoughts:

Pre-Processors
OpenFOAM comes with a mesher (snappyHexMesh) that can take STL surfaces as inputs. For each of your boundary conditions, you will need either sub-surfaces in your STL or separate STL files for each patch/boundary condition. To read in IGES, you may want to look at Engrid, which is also a mesher. I personally do not use this software but i do know that it is widely used by OpenFOAM users. If you can output STL files directly from your CAD software that will maek meshing easier in Snappy. I tend to construct all my geometries in Blender bc i post process some in blender and wanted to shrink down my tools that i used to not be too scatter brained.

Post-Processing
You can use the sampling tools in OpenFOAM and also paraview. This is all I use.

GUI's
Here is a list of GUI's for OpenFOAM.

M_RED · May 16, 2014, 11:59

Awesome.
enGRID seems to be working great so far!!

You wouldn't know if it is possible to multiple select several faces to assign them to a boundary do you? the click "p" and then "s" seems to only let me do one at a time... (in engrid)

chegdan · May 16, 2014, 12:16

Glad you are liking enGrid!

Try posting questions on the enGrid forum

http://www.cfd-online.com/Forums/engrid/

Good luck!

M_RED · May 16, 2014, 14:12

Thanks,

I did exactly that, but no reply. Searched as much as I could, and I can't find away to click more than one surface at a time. crazy frustrating!

chegdan · May 16, 2014, 17:01

If you can convert the CAD to STL surfaces then you can try HELYX-OS. You can look over the presentations about how to use HELYX-OS at

the 8th OpenFOAM Workshop.

and look over the thread

http://www.cfd-online.com/Forums/ope...pyhexmesh.html

For details on snappyHexMesh, look at

SnappyHexMesh on the OpenFOAM wiki (with links to tutorials)

Good luck.

Disclaimer: I work for the company that develops HELYX-OS

May 14, 2014, 13:14	OPEN_FOAM for and idiot?	#1
M_RED New Member James M Join Date: May 2014 Posts: 6 Rep Power: 11	Hello Everyone, First, my background in CFD is decent, but with expensive commercial software, i.e. Ricardo Vectis, AVL FIre, and Fluent for Catia. I know what I want to get out of the simulation, I just have no idea about anything at all on OPENfoam Now, I am finding myself in a situation where i need to do some preliminary / first past sort of simulation on some ducting to evaluate if changes are OK. Basically, I have a duct, it enters a plenum and 5-7 ducts exit, each with a restrictor/throttling plate. I have a current design, and a crappy previous work .pdf, that shows volume flow rate is balanced and basic acceptable level of pressure drop. Everything is steady state. I want to be able to change the plenum, and tweak it until I show the same mass flow rate, and pressure drop. I have looked through the Wikis and opensource stuff, but it seems the windows based one are lacking something. (like ease of use..) or aren't actually free. Can anyone recommend a set of programs, one that are actually free to use, and two let me do the basic pre-processing, i.e. meshing from an igs file, and setting up b/c's, and something to actually post-process too. (I think paraview may have that one covered?) Am I silly to think meshing and set up is the same GUI? Also, crap, I can't edit the title.... Oh the irony...

May 16, 2014, 11:59	Thank you!!!!!	#3
M_RED New Member James M Join Date: May 2014 Posts: 6 Rep Power: 11	Awesome. enGRID seems to be working great so far!! You wouldn't know if it is possible to multiple select several faces to assign them to a boundary do you? the click "p" and then "s" seems to only let me do one at a time... (in engrid)

May 14, 2014, 15:21		#2
chegdan Senior Member Daniel P. Combest Join Date: Mar 2009 Location: St. Louis, USA Posts: 621 Rep Power: 0	James, Welcome! First off, your title actually caught my attention so I call that a win if you can get traffic on your posts. Secondly, this level of frustration and "what do I do next?" is a coherent state that most all of us have reached at some point Now, here are some thoughts: Pre-Processors OpenFOAM comes with a mesher (snappyHexMesh) that can take STL surfaces as inputs. For each of your boundary conditions, you will need either sub-surfaces in your STL or separate STL files for each patch/boundary condition. To read in IGES, you may want to look at Engrid, which is also a mesher. I personally do not use this software but i do know that it is widely used by OpenFOAM users. If you can output STL files directly from your CAD software that will maek meshing easier in Snappy. I tend to construct all my geometries in Blender bc i post process some in blender and wanted to shrink down my tools that i used to not be too scatter brained. Post-Processing You can use the sampling tools in OpenFOAM and also paraview. This is all I use. GUI's Here is a list of GUI's for OpenFOAM.

May 16, 2014, 12:16		#4
chegdan Senior Member Daniel P. Combest Join Date: Mar 2009 Location: St. Louis, USA Posts: 621 Rep Power: 0	Glad you are liking enGrid! Try posting questions on the enGrid forum http://www.cfd-online.com/Forums/engrid/ Good luck!

May 16, 2014, 14:12		#5
M_RED New Member James M Join Date: May 2014 Posts: 6 Rep Power: 11	Thanks, I did exactly that, but no reply. Searched as much as I could, and I can't find away to click more than one surface at a time. crazy frustrating!

May 16, 2014, 17:01		#6
chegdan Senior Member Daniel P. Combest Join Date: Mar 2009 Location: St. Louis, USA Posts: 621 Rep Power: 0	If you can convert the CAD to STL surfaces then you can try HELYX-OS. You can look over the presentations about how to use HELYX-OS at the 8th OpenFOAM Workshop. and look over the thread http://www.cfd-online.com/Forums/ope...pyhexmesh.html For details on snappyHexMesh, look at SnappyHexMesh on the OpenFOAM wiki (with links to tutorials) Good luck. Disclaimer: I work for the company that develops HELYX-OS