problem with use of opemfoam

mtouil · April 27, 2009, 05:39

I am beginner and I need to use openfoam, but I did not know how and what the difference between the pre-processing , solving and post-processing?
thank for you

grtabor · April 27, 2009, 09:55

Same as for any other CFD code. Pre-processing refers to the steps you take to set up the case you want to run; geometry and mesh generation, setting physical and numerical coefficients. Solving consists of actually running the code to generate numbers. Post-processing is manipulating those numbers to provide answers - this can involve graphical display (paraFoam) or data processing (eg. evaluating drag forces)

Gavin

mtouil · April 28, 2009, 03:19

thanks Gavin

mtouil · April 28, 2009, 03:21

what's the best pre and post processing that is easy to handle

gwierink · April 28, 2009, 03:38

For pre-processing there are many tools, it is a matter of taste and resources. You need to generate a mesh in some meshing program like Gambit (is expensive), Gridgen (also costs), Gmsh (is free, I believe), Salome (is free), Cubit (costs a bit), or some other program. For post-processing you can use ParaView as paraFoam or you can also do nice post-processing with Matlab. Of course, you can also use a more commercial post-processing program, but that costs.

Hope this informs you abit.

Regards,

Gijsbert

wolle1982 · April 30, 2009, 06:12

hi mtouil,

since i think you only want to use opensource (free) tools, i advice you to take the openfoam internal tool "blockMesh" for simple meshes (blocks, shapes, 2D, ...) and salome meca for more complex geometries (triangle, quads,...). gmsh is free an very simple, but only creates tetra-meshes. for CFD you might better use hexa-meshes.

another pre-tool would be engrid from the company egits its for free and can also create structured boundary layers. also a good tool (but hard to learn) sit the openfoam internal program snappyhexmesh. it ca (with some errors and problems) create very complex meshes with a boundary layer added. see those many forum threads here.

grtabor is right: paraVierw is a very nice and very good postprocessor.

creating a 3D geometry would be your hardest part, if you don't have a CAD program.

April 27, 2009, 05:39	problem with use of opemfoam	#1
mtouil New Member Mohammed TOUIL Join Date: Apr 2009 Posts: 8 Rep Power: 17	I am beginner and I need to use openfoam, but I did not know how and what the difference between the pre-processing , solving and post-processing? thank for you

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April 27, 2009, 09:55		#2
grtabor Senior Member Gavin Tabor Join Date: Mar 2009 Posts: 181 Rep Power: 17	Same as for any other CFD code. Pre-processing refers to the steps you take to set up the case you want to run; geometry and mesh generation, setting physical and numerical coefficients. Solving consists of actually running the code to generate numbers. Post-processing is manipulating those numbers to provide answers - this can involve graphical display (paraFoam) or data processing (eg. evaluating drag forces) Gavin

April 28, 2009, 03:19		#3
mtouil New Member Mohammed TOUIL Join Date: Apr 2009 Posts: 8 Rep Power: 17	thanks Gavin

April 28, 2009, 03:21		#4
mtouil New Member Mohammed TOUIL Join Date: Apr 2009 Posts: 8 Rep Power: 17	what's the best pre and post processing that is easy to handle

April 28, 2009, 03:38		#5
gwierink Senior Member Gijsbert Wierink Join Date: Mar 2009 Posts: 383 Rep Power: 18	For pre-processing there are many tools, it is a matter of taste and resources. You need to generate a mesh in some meshing program like Gambit (is expensive), Gridgen (also costs), Gmsh (is free, I believe), Salome (is free), Cubit (costs a bit), or some other program. For post-processing you can use ParaView as paraFoam or you can also do nice post-processing with Matlab. Of course, you can also use a more commercial post-processing program, but that costs. Hope this informs you abit. Regards, Gijsbert

April 30, 2009, 06:12		#6
wolle1982 Senior Member Wolfgang Heydlauff Join Date: Mar 2009 Location: Germany Posts: 136 Rep Power: 21	hi mtouil, since i think you only want to use opensource (free) tools, i advice you to take the openfoam internal tool "blockMesh" for simple meshes (blocks, shapes, 2D, ...) and salome meca for more complex geometries (triangle, quads,...). gmsh is free an very simple, but only creates tetra-meshes. for CFD you might better use hexa-meshes. another pre-tool would be engrid from the company egits its for free and can also create structured boundary layers. also a good tool (but hard to learn) sit the openfoam internal program snappyhexmesh. it ca (with some errors and problems) create very complex meshes with a boundary layer added. see those many forum threads here. grtabor is right: paraVierw is a very nice and very good postprocessor. creating a 3D geometry would be your hardest part, if you don't have a CAD program.