[blockMesh] BlockMesh: Strange interface between blocks

dancfd · May 25, 2010, 20:42

Hello all,
I am a beginner at OF1.6 and I am struggling to understand the problem with a C-grid I created for an airfoil. As shown in the pictures of the mesh, the interface between blocks 0-1 and 2-3 feature a "crossover" of the mesh from one surface of the 2-D mesh to the other. I do not get any errors when running blockMesh or paraView, yet this inconsistency persists. I would appreciate any help you could offer.

Regards,

Dan

dancfd · May 26, 2010, 19:23

I apologize for bothering the board with a rookie error. For those who are curious, I had not defined the blocks with a right-hand coordinate system as required in User Guide page U-134. It was convenient to use left-handed coordinate systems in some blocks so that I could use the same expansion ratio in the y-direction for all blocks. Now it is a matter of using the inverse expansion ratio for the blocks I had arranged in a left-handed coordinate system.

Dan

kjetil · June 8, 2010, 10:01

Right. BlockMesh is strict on how you define your blocks.

Are you attempting to reproduce the Fluent tutorial for an airfoil? Seems like you have quite a coarse mesh, and to be "missing" a mesh-section behind the airfoil. But you might parhaps have thought of this already

dancfd · June 8, 2010, 16:54

In fact I have never used Fluent, but it is good to know that there is a similar tutorial out there. I agree, the mesh is very coarse, and this was done intentionally to more effectively show the "disturbance" in the mesh. I did try several refined meshes, but the problem did not disappear until I fixed the left-handed coordinate system.

I appreciate your reply.

Regards,
Dan

May 26, 2010, 19:23	Found problem	#2
dancfd Senior Member Daniel Join Date: Jul 2009 Location: Montreal, Canada Posts: 156 Rep Power: 16	I apologize for bothering the board with a rookie error. For those who are curious, I had not defined the blocks with a right-hand coordinate system as required in User Guide page U-134. It was convenient to use left-handed coordinate systems in some blocks so that I could use the same expansion ratio in the y-direction for all blocks. Now it is a matter of using the inverse expansion ratio for the blocks I had arranged in a left-handed coordinate system. Dan

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June 8, 2010, 10:01		#3
kjetil Senior Member Join Date: Mar 2009 Location: Norway Posts: 137 Rep Power: 17	Right. BlockMesh is strict on how you define your blocks. Are you attempting to reproduce the Fluent tutorial for an airfoil? Seems like you have quite a coarse mesh, and to be "missing" a mesh-section behind the airfoil. But you might parhaps have thought of this already

June 8, 2010, 16:54		#4
dancfd Senior Member Daniel Join Date: Jul 2009 Location: Montreal, Canada Posts: 156 Rep Power: 16	In fact I have never used Fluent, but it is good to know that there is a similar tutorial out there. I agree, the mesh is very coarse, and this was done intentionally to more effectively show the "disturbance" in the mesh. I did try several refined meshes, but the problem did not disappear until I fixed the left-handed coordinate system. I appreciate your reply. Regards, Dan