Mashing problem due to projections
 

Hi all,

I am trying to deliver an assignment for my students but, all of them came up with this problem, even though they followed the correct procedure that gave me the precise result.

This is the image that every body gets:https://s23.postimg.org/gqk592sjf/preview.jpg

Does anybody know what the problem could be?

Thanks in advance for any help!

Do you think there're telepaths here? This image tells nothing. The problem most likely is come from meshing controls. But where are they? Also it is good to know how the geometry is structured.

Dear Sir,

I apologize if I did not provide enough details. I don't think there are telephats over there but people with a lot more experience than me.

By the way, the geometry is structured as the following image can show( hopefully will be clearer than the previous one)


https://s28.postimg.org/u4tzwejm5/preview_geom.png

In the middle of the domain there is a NACA0010 airfoil.

I divided the domain using lines and projecting the lines on the surface. In this way I can obtain 10 edges and 6 faces.( With bolean operation I have subtracted the airfoil from the domain since I have created a single body)

I inserted the edge sizing on each edge by number of division and I inserted the bias in order to obtain a structured mesh with a concentration of elements denser near the airfoil and less in the far field. The bias factor is 50 and the number of elements is 100 on each edge.

I hope that this can help for the solution...

Better share your project

Thanks a lot for your support.I do appreciate.

I attach the .zip file which contains all the files.

I hope it helps.

Zoom in on trailing edge and you'll see what is on image. I don't think this is how you want it to be.

Definitely not. Thanks a lot. Is it possible that the meshing problems come from there?

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Sure it can. Also I don't like your split on leading edge. There's almost 0 angle between airfoil and vertical edge.

Sorry but I don't understand what you mean. The vertical line should be tangent to the leading edge therefore the angle is 90...can you explain me where is the mistake?

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Angle between vertical (split) edge and tangent line to airfoil in its stagnation point is almost 0. It will prevent meshing or lead to bad elements.

So I should drag the vertical line precisely on the stagnation point?


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Arghhhh! No it's already there. Look on image.

Thanks a lot!

I do appreciate your help. I will try to follow your method. I will post the meshing if it will come correctly

Dear Antanas,

After having tried for more than one day this is the final result. I am posting the entire project. I have used your method, this time on a NACA4420 airfoil.

The quality is excellent except for one face which has not been meshed. I am not able to find the problem.

I attach the image but I am not able to attach the entire project because .zip format is to big.
https://s30.postimg.org/t485i2grl/preview_geom.png

https://www.cfd-online.com/Forums/<a...nn/preview.pnghttps://s29.postimg.org/iq0npo5pj/preview.png

I can't say anything based on your images. You may use some filehosting if your project is big.

Hope this works:

http://www61.zippyshare.com/v/v2bWxmw8/file.html

Well. IMO you did your geometry wrong. You've got double veritices in two locations (see 1st image). Note that in one location they are separated by small distance. It is not necessary to make one body. You may split your body into separate bodies (each face as separate body) and combine 'em as multibody part to get conformal mesh.
Also your airfoil has got blunt trailing edge (maybe as a result of geometry creation process) and topology that you use is not good for this, because of bad angles (see 2nd image).

I tried to follow your geometry with the horizontal line on the right. I'll split the face on the right with a ZX plane.

Regarding the blunt T.E. it came from NACA airfoils generator with a close trailing edge...What kind of topology should I use?

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Airfoil generator gives you finit number of points. You should ensure that there's corner point on trailing edge. If it there, then problem is in spline smoothing during conversion to curve in DesignModeler.

It has it. I cross checked with excel and matlab. this is the plot I get.

https://s24.postimg.org/eyfz14es5/airfoil.png