[Gmsh] 2D Mesh for OpenFOAM: boundary layer field and extrusion

Fri Feb 9 18:38:56 CET 2018

Hi Christophe,

As a further follow up, using the latest version, the BL is now included in
the extrusion and the physical group. However, when it is converted to
OpenFOAM mesh, the BL is given is still given it's own patch. I suppose
this is because *gmshToFoam* uses the *mesh partitions*, and *not the
physical groups* to determine patches. However, what is more peculiar is
that the patch only includes one side, even when I specify the extruded
features in the BoundaryLayer Field.

In this simple case, I can alter the OF boundary file so that the BL is
considered a part of the rest of the domain. However, issues arise when the
BL is split over a number domains. So for example, if I alter the
BoundaryLayer Field such that there is also a BL around the blades (see the
attached geo file). The correct physical groups are specified, but when I
use gmshToFoam, a patch is automatically defined as one side of the BL,
which spreads out over two domains.

I suppose this is an issue with *gmshToFoam* and not with gmsh. I will post
this same issue to OF mailing-list.

James

On Fri, Feb 9, 2018 at 4:47 PM, James Gross <jgross0227 at gmail.com> wrote:

> Ubuntu 16.04.01
>
> On Fri, Feb 9, 2018 at 4:40 PM, <cgeuzaine at uliege.be> wrote:
>
>> Weird - which system?
>>
>> -- Sent from my phone
>>
>> On 9 Feb 2018, at 16:40, James Gross <jgross0227 at gmail.com> wrote:
>>
>> Hi Christophe,
>>
>> I pulled the latest version and installed it. However, I can't seem to
>> launch the GUI from command line using *gmsh* command anymore to
>> visually inspect the meshes. Is there another way to launch it now?
>>
>> When configuring I enabled Python wrappers (which I've been meaning to do
>> anyway), but I don't think that would make a difference with how the GUI is
>> launched.
>>
>> Thanks,
>> James
>>
>> On Fri, Feb 9, 2018 at 2:51 PM, Christophe Geuzaine <cgeuzaine at uliege.be>
>> wrote:
>>
>>>
>>> Hi James - Try with the latest automated snapshot and let me know.
>>>
>>> On 9 Feb 2018, at 15:34, James Gross <jgross0227 at gmail.com> wrote:
>>>
>>> Hi Christophe,
>>>
>>> First of all, thank you for taking the time to help.
>>>
>>> As a preliminary, I am using the latest stable release i.e. 3.0.6.
>>>
>>> It seems I am not getting the same as you for the given code. Looking at
>>> all the features, I get the following.
>>>
>>> <Full.jpg>
>>> 
>>> So that the BL has seemed to be split into its own partition.
>>>
>>> By itself, this wouldn't be a problem. However, when I look through the
>>> surfaces in the elementary entities, I find that one of the surfaces
>>> includes the BL.
>>>
>>> <With.jpg>
>>> However, the other side does not.
>>>
>>> <Without.jpg>
>>> Furthermore, there isn't any surface contained in the visibility dialog
>>> box that corresponds to the missing BL.
>>>
>>> This is before even specifying any physical groups. Using the indices of
>>> the extruded object to specify physical groups gives the same behaviour.
>>>
>>> James
>>>
>>>
>>>
>>> On Thu, Feb 8, 2018 at 10:13 PM, Christophe Geuzaine <
>>> cgeuzaine at uliege.be> wrote:
>>>
>>>>
>>>> Hi James,
>>>>
>>>> The file seems to work fine over here, generating the full 3D mesh as
>>>> expected… Try with the latest automated snapshot?
>>>>
>>>> Christophe
>>>>
>>>> <Pump_ExtB.png>
>>>>
>>>> On 8 Feb 2018, at 16:05, James Gross <jgross0227 at gmail.com> wrote:
>>>>
>>>> Hi everyone,
>>>>
>>>> I am looking to create a 2D mesh for a simulation of a pump in OF. I
>>>> would like to use BoundaryLayer Field to create a structured mesh for the
>>>> boundary layer, with an unstructured mesh in the rest of the flow field.
>>>>
>>>> All is good for the purely 2D mesh, however when I extrude the surface
>>>> to make the mesh for OF, the boundary layer does not seem to be fully
>>>> extruded, as only the one side that specified in the BoundaryLayer Field is
>>>> included when I label the Physical Surface.
>>>>
>>>> My understanding is that geometrical features from both extruded and
>>>> non-extruded side needs to be specified during the BoundaryLayer Field
>>>> call. However this is fairly cumbersome, as I need to find the labels for
>>>> all of the extruded features.
>>>>
>>>> Is there another way to do this?
>>>>
>>>> I have attached a geo file that creates a geometry, extrudes it, and
>>>> meshes it.
>>>>
>>>> Any help/advice that anyone can offer would be greatly appreciated.
>>>>
>>>> Regards,
>>>> James
>>>> <Pump_ExtB.geo>_______________________________________________
>>>> gmsh mailing list
>>>> gmsh at onelab.info
>>>> http://onelab.info/mailman/listinfo/gmsh
>>>>
>>>>
>>>> —
>>>> Prof. Christophe Geuzaine
>>>> University of Liege, Electrical Engineering and Computer Science
>>>> http://www.montefiore.ulg.ac.be/~geuzaine
>>>>
>>>> Free software: http://gmsh.info | http://getdp.info | http://onel
>>>> ab.info
>>>>
>>>>
>>>
>>> —
>>> Prof. Christophe Geuzaine
>>> University of Liege, Electrical Engineering and Computer Science
>>> http://www.montefiore.ulg.ac.be/~geuzaine
>>>
>>> Free software: http://gmsh.info | http://getdp.info | http://onelab.info
>>>
>>>
>>
>
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