2D-Mesh with blocking? possible?

The_Kaiser · October 24, 2016, 04:15

Hey,

I tried to do a blocking of my 2D Geometry with HEXA_BLOCK. Unfortunately, I get only 3D hexa blocks (I know, I know, a hexa is 3D. But I hoped to get sth 2D). I want to do it in 2D, to easily vary the thickness and number of elements in the third dimesnion with the TRANSLATE option. (want to use it in OpenFOAM, unstationary simulation). Is it possible to do somehow a blocking of a 2D geometry? Maybe splitting the sourface in "blocks" in my CAD-program, then mesh it with ANSA? Could this work?

Thanks in advance

vangelis · October 24, 2016, 07:28

Hi there,

Indeed ANSA hexablock is meant for 3D meshing.

You could of course create these Boxes and only mesh one of their facets only, but I think this is not an efficient approach.

I would therefore recommend that you work on the level of geometry in xy plane, and with CUT operations, cut parallelogram patches that you can mesh with MAP QUAD mesh. The functions that you should use for meshing are then:

Perimeters>Length, Number and Spacing
Have also in mind the function Perimeters Align, which can be used to "copy" a distribution from one perimeter to another.

After meshing all macros with map quad mesh, you can, as you write, use Volumes>Extrude>translate in z coordinate and create one cell thickness for OpenFOAM 2D.

Remember to use Elements>Vol2Shell>Skin to create shell mesh in the free exposed facets of the created hexa mesh, so that you can assign BCs on them

Hope this helps

Vangelis

The_Kaiser · October 25, 2016, 09:17

Hey,

Thanks for the advise, it works fine so far!

A problem comes after using Elements>Vol2Shell>Skin. I get the shell, but the problem is, every mesh element gave me 1 face. So when I have over a milion faces, it's kinda impossible to assign the boundary conditions... Help again please?

vangelis · October 25, 2016, 09:50

I forgot to mention that for quick selection you should activate the Feature Angle selection tool at the bottom centre of ANSA GUI next to ENT and PID selection. In this way with one click you can pick a whole area within the user specified feature angle (by default 40deg)
Vangelis

The_Kaiser · October 28, 2016, 05:46

Works so good. You are like a magician

Thanks

October 24, 2016, 04:15	2D-Mesh with blocking? possible?	#1
The_Kaiser New Member Join Date: Mar 2016 Posts: 29 Rep Power: 10	Hey, I tried to do a blocking of my 2D Geometry with HEXA_BLOCK. Unfortunately, I get only 3D hexa blocks (I know, I know, a hexa is 3D. But I hoped to get sth 2D). I want to do it in 2D, to easily vary the thickness and number of elements in the third dimesnion with the TRANSLATE option. (want to use it in OpenFOAM, unstationary simulation). Is it possible to do somehow a blocking of a 2D geometry? Maybe splitting the sourface in "blocks" in my CAD-program, then mesh it with ANSA? Could this work? Thanks in advance Last edited by The_Kaiser; October 24, 2016 at 06:23. Reason: idea for solving

October 28, 2016, 05:46		#5
The_Kaiser New Member Join Date: Mar 2016 Posts: 29 Rep Power: 10	Works so good. You are like a magician Thanks vangelis likes this.

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October 24, 2016, 07:28		#2
vangelis Senior Member Vangelis Skaperdas Join Date: Mar 2009 Location: Thessaloniki, Greece Posts: 287 Rep Power: 21	Hi there, Indeed ANSA hexablock is meant for 3D meshing. You could of course create these Boxes and only mesh one of their facets only, but I think this is not an efficient approach. I would therefore recommend that you work on the level of geometry in xy plane, and with CUT operations, cut parallelogram patches that you can mesh with MAP QUAD mesh. The functions that you should use for meshing are then: Perimeters>Length, Number and Spacing Have also in mind the function Perimeters Align, which can be used to "copy" a distribution from one perimeter to another. After meshing all macros with map quad mesh, you can, as you write, use Volumes>Extrude>translate in z coordinate and create one cell thickness for OpenFOAM 2D. Remember to use Elements>Vol2Shell>Skin to create shell mesh in the free exposed facets of the created hexa mesh, so that you can assign BCs on them Hope this helps Vangelis

October 25, 2016, 09:17		#3
The_Kaiser New Member Join Date: Mar 2016 Posts: 29 Rep Power: 10	Hey, Thanks for the advise, it works fine so far! A problem comes after using Elements>Vol2Shell>Skin. I get the shell, but the problem is, every mesh element gave me 1 face. So when I have over a milion faces, it's kinda impossible to assign the boundary conditions... Help again please?

October 25, 2016, 09:50		#4
vangelis Senior Member Vangelis Skaperdas Join Date: Mar 2009 Location: Thessaloniki, Greece Posts: 287 Rep Power: 21	I forgot to mention that for quick selection you should activate the Feature Angle selection tool at the bottom centre of ANSA GUI next to ENT and PID selection. In this way with one click you can pick a whole area within the user specified feature angle (by default 40deg) Vangelis