#5 NaN error when SMTH the profile

[KOY]

Hi,
Thank you for this great software....it helped me a lot.
I have problem, when I try to generate grid of an airfoil using SMTH, some times it gets error message:
"Warning: could not find interpolants.
s: NaN cdfsmax: NaN
Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO"
despite that alla values entered are ok and was taken from an excel sheet.
Do you have any idea about this error??
attached the input file.

Thank you.

[Dan]

Have you looked at that profile? It's no wonder it doesn't work. It's got multiple loops and self-intersections. Construct2D is only meant for use with single profiles forming a loop. I've attached an image of your profile.

[KOY]

Hi Dan,
Thank you for your response, it is now working.
as you can see, I am simulating a rough airfoil with some concave regions. Do you have any ideas what is the best way to do that? I have read the user manual and read about ELLP solver and FUNI values, Is there any other ideas other than that?

Best Regards,

[Dan]

If they are small bumps like in the profile you posted, you will need to use the BUFF option to generate the grid instead of SMTH, because the smoothing procedure will not preserve them. Be aware that this will result in the number of grid points along the surface being equal to the number of points in the airfoil file, which in the case you posted was huge (2000+ or something). So you may need to do some manual adjustment of the input file to remove unneeded points.

In general, though, it will be tough to get a good quality grid on a bumpy profile with small concave regions. It may not be possible at all with a structured grid.

[Mikkel Paulsen]

I have a similar issue trying to generate a mesh for a simple circle, and i get the same error message. I looked at the profile and it doesnt seen to have any loops, but it still wont work. Im very new to this, but i cant see why it wont work. I have attached the dat file im using if anyone would care to take a look.
I would really appreciate any help i can get!