[Gmsh] generating an SU2 Euler mesh based on STEP input

Thu Mar 28 09:24:57 CET 2019

Hi Christophe,

great picture! How did you create it? When I use the clipping tool it cuts everything.
How can the clipping be applied to just the surrounding volume?
Many thanks in advance for your answer!

Best regards,
Michael

Von: gmsh <gmsh-bounces at ace20.montefiore.ulg.ac.be> Im Auftrag von Christophe Geuzaine
Gesendet: Donnerstag, 28. März 2019 08:54
An: Johannes Dillinger <jojodillinger at gmail.com>
Cc: Gmsh <gmsh at onelab.info>
Betreff: Re: [Gmsh] generating an SU2 Euler mesh based on STEP input

> On 27 Mar 2019, at 22:59, Johannes Dillinger <jojodillinger at gmail.com<mailto:jojodillinger at gmail.com>> wrote:
>
> Hi Christophe,
>
> amazing... thank you for this simplification, really cool!
>
> So the next question would be, if there is an automatic way to specify the surfaces belonging to the model ("wingfuselage") and the farfield ("farfield"); I am only able to hard-code it, but there are probably much smarter ways.. I tried something like
> Physical Surface("wingfuselage") = Boundary{Volume{v()};};
> But could not get it to work..
>
> And then I tried to adapt mesh density on the wing and fuselage edges via a Threshold and Restrict Field. But it seems overly complicated the way I do it. Do you maybe have a quick suggestion on how to adapt the meshsize in areas of higher curvature, while leaving it untouched on the farfield?
>

Here's an example:

[cid:image001.png at 01D4E548.1B93BCE0]

> I attached again the current status of the .geo-file..
>
> Thanks so much again!
> Best regards,
>
> Johannes
>
>
>
>
> Am Mi., 27. März 2019 um 19:58 Uhr schrieb Christophe Geuzaine <cgeuzaine at uliege.be<mailto:cgeuzaine at uliege.be>>:
>
> Hi Johannes,
>
> I can't reproduce the crashes when deleting the curves... Your file also seems very complicated. I would just do:
>
> SetFactory("OpenCASCADE");
> Geometry.OCCTargetUnit = "M";
> v() = ShapeFromFile("wing_fuselage.step");
> Box(3) = {-5, -5, -5, 10, 10, 10};
> out() = BooleanDifference{ Volume{3}; Delete; }{ Volume{v()}; Delete; };
>
> out() will contain the volume of interest.
>
> Christophe
>
>
>> On 27 Mar 2019, at 19:29, Johannes Dillinger <jojodillinger at gmail.com<mailto:jojodillinger at gmail.com>> wrote:
>>
>> Dear all,
>>
>> I'm looking for a suitable way to "quickly" generate Euler meshes for SU2 CFD analysis.
>> So the usual setup is a (hopefully rather simple) STEP model of a wing-fusleage part for example, that I want to mesh in GMSH.
>>
>> I attached a sample STEP and the geo-file that I have been working on, but I cant seem to find the errors..
>>      • First I merge the STEP-file and reverse some surfaces (that apparently are oriented in the wrong direction)..
>>      • I generate a surface loop of the outer surfaces for defining outer volume later on. Here the first weird thing happens: the loop command generates surfaces 17, 18, and curves 39-44
>>      • I delete surfaces 17 and 18, since they later on will make problems otherwise
>>      • I also delete the imported volumes
>>
>> I then generate a farfield/bounding box, and also here, the loop command generates additional surfaces 1007 to 1010, and I cant figure out why.. Anyway, I again delte those, since they will cause problems otherwise.
>>
>> The last problem which really stops me from continuing is the outer volume that I generate with the "Volume" command in line 50. This one again generates a surface 1009, that I cant delete anymore..
>> So the surface will be 2D meshed and maybe then leads to the problem that the outer volume cannot be meshed.
>>
>> I guess thats enough questions and porblems for now. Once solved, it would be great if you could help me with mesh density and so on (already in the geo though), but thats for later..:-)
>>
>> So, to sum up:
>>      • is the general methodology I use ok?
>>      • how can I avoid the additional surfaces and curves to be created?
>>      • which problem still exists that does not allow for the 3D mesh generation?
>> Thank you so much in advance!
>> Best regards,
>>
>> Johannes
>>
>>
>>
>>
>> <wing_fuselage.geo><wing_fuselage.step>_______________________________________________
>> gmsh mailing list
>> gmsh at onelab.info<mailto: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
>
>
>
> <wing_fuselage.geo>

—
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine

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