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-   -   Curve is Lines!! , visual Or real? (http://www.cfd-online.com/Forums/fluent/121247-curve-lines-visual-real.html)

m5edr July 24, 2013 10:57

Curve is Lines!! , visual Or real?
 
2 Attachment(s)
Hi experts ,
I have simple question

My geometry contains blade where the leading edge of the blade is a CURVE but Fluent shows it as group of lines (figure 1)

Is this just visual problem or real problem and hence effect on results.. I should noted that my geometry was built SolidWorks and i'm sure that it was curve not lines

thanks in advance

Far July 24, 2013 14:49

It simply shows that your mesh is coarse in that region. Or may be you be have zoomed too much :o

m5edr July 24, 2013 20:07

Thanks far for replay
Quote:

Originally Posted by Far (Post 441769)
It simply shows that your mesh is coarse in that region. Or may be you be have zoomed too much :o

no it is not the mesh (it also appears in same way in ICEM) , and also i'm not zooming too much :confused:

I can upload my Case file if you need

m5edr July 25, 2013 11:22

here is the case file http://www.4shared.com/file/DseLJUYW/Case.html

I wonder that the circle (at the hub) also appera as a group of lines while the enclosure's curves domain (which contains the blade) is typical curves in general

m5edr July 27, 2013 15:31

Any recommendation?

Far July 27, 2013 16:36

It is the problem of meshing.

If it was not the meshing problem, then it could be due to geometry

m5edr July 27, 2013 16:43

Quote:

Originally Posted by Far (Post 442371)
It is the problem of meshing.

If it was not the meshing problem, then it could be due to geometry

Dear Far,
I choose from fluent Mesh Display menu to display the edges not the faces , is this mean it display the mesh (where is the mesh it is just an edge) !! see Figures pls

Far July 27, 2013 16:55

I have check your mesh file, you have attached in above post.

m5edr July 27, 2013 17:00

Quote:

Originally Posted by Far (Post 442374)
I have check your mesh file, you have attached in above post.

OK thanks Far , sorry for this noise

Quote:

Originally Posted by Far (Post 442371)
If it was not the meshing problem, then it could be due to geometry

But i still don't know what is your recommendation : is this Mesh or Geometry error :confused:

thanks in advance

Far July 27, 2013 17:14

I am saying that if you have faulty (degenerated) geometry like sharp leading edge instead of curved one then even fine mesh cannot do anything. For example by packing more mesh points in sharp leading edge you cannot make it round. Got it!!!

So if you have perfect geometry (you need to confirm it) then it is the problem of mesh.

m5edr July 27, 2013 17:27

Thanks Far , this is Last inquiry
you confirmed that it is not a VISUAL (screen) trick , it is REAL?

Far July 27, 2013 17:32

It is real

mjgraf July 27, 2013 19:19

did not get the case file.

in general using ICEM

using mesh quality, select the surface deviation (surface dev) to essentially show you the deviation/error in the elements face center to the actual surface of the geometry. you can color the mesh with mesh quality (it is a little flaky so you may need to set it, unset it and set it back again).

if your surface is not split so the nose can be in a separate part, then you need to reduce the max deviation in the Part Mesh Setup for the blade surface. Or use the geometry line and surface tools to split the surface in ICEM along a ISO line if you can create a reasonable line.

depending on what you want to look at I would recommend using a hexa for your wind turbine blade.


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