[Gmsh] VB: SV: not multiply connected

Tue Apr 17 17:10:24 CEST 2007

>
> Dear Prof. Christophe Geuzaine
>
> I am so happy that you can help me and thank you very much for the example
> you sent me.
>
> I think it would be good to know more about C-programming than I do. I am
> much better with fortran.
>
> It looks like there are cells inside the building in the mesh you sent me?
> I will use my mesh with CFD-software for calculating the wind around the
> buildings. Therefor I do not want to have a mesh inside the buildings.
>
>>From the information you sent me I tried to make a very simple geo-fil
>> with only 5 buildings. 4 of them are 20 m high and one building 10 m
>> high. 3 of the buildings are connected. If I understand how to mesh this
>> geometry I think I can mesh all geometrys I need to mesh.
>
> How do I mesh this geometry without meshing the buildings?

Hi,

if you want to mesh the air around the building, you will have to define a
big box around the buildings, then define a Physical Volume made of the
big box with the buildings defined as "holes". See tutorial/t4.geo and
t5.geo.

Cheers,

Dave

>
> Will you please help? This is very important for my work.
>
>
>
> Regards,
>
> Lennart Wern
> SMHI
> Swedish Meteorological and Hydrological Institute
> SE-601 76 NORRKÖPING
> Sweden
>
> http://www.smhi.se/cfd
>
> Visiting address: Folkborgsvägen 1
> Email: lennart.wern at smhi.se
> Phone: +46 11 495 81 49
> Fax: +46 11 495 82 50
>
>
>
>
> -----Ursprungligt meddelande-----
> Från: Christophe Geuzaine [mailto:cgeuzaine at ulg.ac.be]
> Skickat: den 6 april 2007 11:57
> Till: Wern Lennart
> Ämne: Re: SV: [Gmsh] not multiply connected
>
> Wern Lennart wrote:
>> Dear Prof. Christophe Geuzaine
>>
>> I am very greatful that you want to help me.
>>
>> What I really want to mesh are many buildings with different building
>> heights, see attached geo-fil. My thoughts was to start 100 m above
>> ground and extrude downwards to the roofs where the buildings are and
>> extrude to the ground around the buildings. The ground are at 0 m.
>>
>> I want to mesh my geometry with hexaedrals or prisms, absolutely not
>> with tetraedrals. I only want to mesh around the buildings, not inside.
>>
>> How can I best mesh around my buildings?
>
>
> I would probably just extrude the surface mesh (I've created a simplified
> example--have a look at the attached file).
>
>
>
>
>
>>
>> I am so happy for all help I can get.
>>
>>
>> Regards,
>>
>> Lennart Wern
>> SMHI
>> Swedish Meteorological and Hydrological Institute
>> SE-601 76 NORRKÖPING
>> Sweden
>>
>> http://www.smhi.se/cfd
>>
>> Visiting address: Folkborgsvägen 1
>> Email: lennart.wern at smhi.se
>> Phone: +46 11 495 81 49
>> Fax: +46 11 495 82 50
>>
>>
>>
>>
>> -----Ursprungligt meddelande-----
>> Från: Christophe Geuzaine [mailto:cgeuzaine at ulg.ac.be]
>> Skickat: den 4 april 2007 14:14
>> Till: Wern Lennart
>> Kopia: gmsh at geuz.org
>> Ämne: Re: [Gmsh] not multiply connected
>>
>> Wern Lennart wrote:
>>> Dear Gmsh-user
>>>
>>> I am a new user of gmsh and I need some assistance.
>>>
>>> I have made a very simple geometry with two volumes that I can mesh
>>> without any problems, see attached file.
>>>
>>> I want to use my mesh in OpenFOAM and I therfor convert it. In the
>>> converting log I get text like the below:
>>>
>>> It seems like the two volumes are not connected. How can I connect
>>> them?
>>> Please help !!!
>>
>>
>> The way you generated the volumes, they are indeed not connected (you
>> extruded the surfaces by 2 different heights).
>>
>> Attached is a version of your geometry that connects the volumes.
>>
>>
>>
>>
>>> ------------------------------
>>> checkCoords : points 1142 and 492 with coordinates:(250 343.75 70)
>>> and (250 343.75 70)  are relatively close to each other. This might
>>> be correct in case of e.g. baffles.
>>> checkCoords : points 491 and 1141 with coordinates:(250 343.75 80)
>>> and (250 343.75 80)  are relatively close to each other. This might
>>> be correct in case of e.g. baffles.
>>> checkCoords : points 490 and 1140 with coordinates:(250 343.75 90)
>>> and (250 343.75 90)  are relatively close to each other. This might
>>> be correct in case of e.g. baffles.
>>> checkCoords : points 488 and 192 with coordinates:(250 375 20) and
>>> (250
>>> 375 20)
>>>  are relatively close to each other. This might be correct in case of
>>> e.g. baffles.
>>>
>>> patch9  146     156     ok (not multiply connected)
>>> patch11 145     155     ok (not multiply connected)
>>> patch33 146     156     ok (not multiply connected)
>>> patch55 145     155     ok (not multiply connected)
>>> ------------------------------
>>>
>>>
>>> Regards,
>>>
>>> Lennart Wern
>>> SMHI
>>> Swedish Meteorological and Hydrological Institute
>>> SE-601 76 NORRKÖPING
>>> Sweden
>>>
>>> Visiting address: Folkborgsvägen 1
>>> Email: lennart.wern at smhi.se
>>> Phone: +46 11 495 81 49
>>> Fax: +46 11 495 82 50
>>>
>>>
>>>
>>>
>>> <<test_1.geo>>
>>>
>>>
>>> ---------------------------------------------------------------------
>>> -
>>> --
>>>
>>> _______________________________________________
>>> gmsh mailing list
>>> gmsh at geuz.org
>>> http://www.geuz.org/mailman/listinfo/gmsh
>>
>>
>> --
>> Prof. Christophe Geuzaine
>> University of Liege, Electrical Engineering and Computer Science
>> http://www.montefiore.ulg.ac.be/~geuzaine
>>
>
>
> --
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science
> http://www.montefiore.ulg.ac.be/~geuzaine
>
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