Hexa meshing 3D aircraft wing from DPW3: Quality improvement
 

Hi everyone,

I am trying to mesh a 3D aircraft wing (finite) which I have downloaded from Drag Prediction Workshop 3. The end away from the symmetry plane is bulged (Fig.1). I was able to create a mesh and failed to load it into Fluent.
I was trying to improve the quality but felt it difficult to satisfy the 'Angle' criterion at the tip of the wing (Fig2).
Can anyone help me? I have already gone through youtube videos and previous threads in the forum but the geometry is slightly different.:confused:
Please let me know if you want to see the files.

do a split just before the trailing edge's end close to the tip. and then modify the small block to represent the tip curvature

This might help you...

https://www.youtube.com/watch?v=mgjRT4WY_iA

Hi Shereez and Sijal,

Thank you very much for the replies.
I already have a split parallel to the span, close to the tip of the wing and tried to make a O grid for the small block to reduce the the number of skewed cells (Fig). Is that what you mean by modifying the block? Kindly let me know.

BTW, I watch the video tutorials of you both. They are excellent! In fact I learnt most of the things from them only.

show edges and mesh on it...

Please see the figures. That's how the edges and mesh looks like.

you need to create another ogrid in tip region.

Hi,
I have created the O grid. Please see the figures.
But the number of erroneous cells increased!:(

could you please share files?

Hi Dronzer,

the edges in the core of the o-grid need a copy of the edge parameters of the trailing edge. Just have a look how the elements in the blue reagion are distorted to the right.

Moreover, the corners of the o-grid vertices need a proper position. Right now it seems you just offset the trailing edge curves to the o-grid core. This just copies the originial problem to the core of the o-grid.
Reduce the length of the shortest edges (perpendicular to the trailing edge) of the ogrid. Avoid trapezoids with small corner angles.

Also pay attention to projections. a face in the o-grid of the trailing edge has been associated to the side of the wing.

Best regards,
Sebastian

Hi Sijal,

Please find the files attached. I have compressed them into two because the upload size for .zip file is limited by 190kb.

Thank you so much for the help.

Hi Sebastian,

Thank you for the suggestions.
I tried to change the edge parameters to avoid the distortions on the tip (the blue area).
Also I made some attempts to manually adjust the O grid corners after looking at the distorted cells.
Unfortunately, they didn't work out.
Let me try it again.

files are damaged. i only need tin and blk files

Hi,

Sorry for that.
Please see the link below.
https://wetransfer.com/downloads/b54...6110550/2c6cea

Solved it!!!
 

Hi guys,

Finally I was able to solve it!!
I got the quality and determinant above 0.3 and angle above 18 deg.
Thanks a lot to you guys for the suggestions and more importantly for the video tutorials.
The mistakes which I believe I have made are,
1) In my blocking method
2) The offset value I have chosen for O grid around the wing was high

Can anyone please tell me how you decide the offset value and if it is recommended to use the 'Link shape' option in it?

You can use relative or absolute value for offset.

It really depends on boundary layer development. So you give absolute value in terms of units. for example if boundary layer is 6 mm thick, provide offset = 7 mm (1 mm factor for safety for calculating value from simple flat plate formulae).

For relative i usually go with 0.2 to 0.4 offset.

Hi Sijal,

Got it!
Thank you for the answer!:)