mesh quality

prince_pahariaa · August 4, 2011, 07:08

what is the acceptable range of quality of mesh in gambit ?? can it be generalize for every case ??

-mAx- · August 4, 2011, 09:13

it depends on your mesh (hexa, tetra, etc...)
I would say 0.9 for tetra and 0.8 for hexa.
But you can export a mesh which skewness doesn't exceed 0.97.
In every case, you may run a check mesh in your solver.
Running a model, which mesh quality is about 0.95 doesn't necessary means that you will have problem (peaks in Residuals, or exotic solution). But it is possible

prince_pahariaa · August 5, 2011, 01:52

Thanks max..

I was getting mesh qulaity of around .25-.30 if i use tetra mesh.. and around .79 if i use hexa..

I am getting entirely different results if i only change the mesh type. with tetra mesh my mass flux is balanced and i am getting some realistic output. But with hexa mesh mass flux itself not balanced. I have changed nothing in boundary condition or anything except mesh type (from tetra to hexa mesh)..

Do u have any idea where the problem may be.. ??

Once again thanks a lot..

-mAx- · August 5, 2011, 01:56

Without more information, it is quite difficult to evaluate the situation.
What are you modeling? Post picture of your mesh with tetra and hexa

prince_pahariaa · August 8, 2011, 02:53

Hey max

i guess i found out what problem is. I checked the grid in fluent and found unexpected wall in my geometry which is hindering the flow. Might be if i remove that wall, i will get my solution.

I really appreciate your help.

-mAx- · August 8, 2011, 02:56

unwanted walls may come from not-connected surfaces.
>> Surfaces / Connect / All

August 4, 2011, 07:08	mesh quality	#1
prince_pahariaa Member prince Join Date: Jun 2011 Posts: 56 Rep Power: 14	what is the acceptable range of quality of mesh in gambit ?? can it be generalize for every case ??

August 4, 2011, 09:13		#2
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	it depends on your mesh (hexa, tetra, etc...) I would say 0.9 for tetra and 0.8 for hexa. But you can export a mesh which skewness doesn't exceed 0.97. In every case, you may run a check mesh in your solver. Running a model, which mesh quality is about 0.95 doesn't necessary means that you will have problem (peaks in Residuals, or exotic solution). But it is possible __________________ In memory of my friend Hervé: CFD engineer & freerider

August 5, 2011, 01:56		#4
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	Without more information, it is quite difficult to evaluate the situation. What are you modeling? Post picture of your mesh with tetra and hexa __________________ In memory of my friend Hervé: CFD engineer & freerider

August 8, 2011, 02:56		#6
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	unwanted walls may come from not-connected surfaces. >> Surfaces / Connect / All __________________ In memory of my friend Hervé: CFD engineer & freerider

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[ICEM] Generating Mesh for STL Car in Windtunnel Simulation	tommymoose	ANSYS Meshing & Geometry	48	April 15, 2013 04:24
[ICEM] trouble with mesh quality from ICEM in CFX Solver	escher25	ANSYS Meshing & Geometry	0	February 28, 2011 07:38
[snappyHexMesh] mesh quality control and fix	tachyon_me	OpenFOAM Meshing & Mesh Conversion	0	October 6, 2009 12:48
fluent add additional zones for the mesh file	SSL	FLUENT	2	January 26, 2008 11:55
Icemcfd 11: Loss of mesh from surface mesh option?	Joe	CFX	2	March 26, 2007 18:10

August 5, 2011, 01:52		#3
prince_pahariaa Member prince Join Date: Jun 2011 Posts: 56 Rep Power: 14	Thanks max.. I was getting mesh qulaity of around .25-.30 if i use tetra mesh.. and around .79 if i use hexa.. I am getting entirely different results if i only change the mesh type. with tetra mesh my mass flux is balanced and i am getting some realistic output. But with hexa mesh mass flux itself not balanced. I have changed nothing in boundary condition or anything except mesh type (from tetra to hexa mesh).. Do u have any idea where the problem may be.. ?? Once again thanks a lot..