Panel Method - Could not find matching edge!

[Michael Hughes]

Hey Everyone,

I'm a relatively new OpenVSP user and have been working through the online tutorials and have really been enjoying the program. I've been running some simulations in VSPAero using VLM method successfully, but have run into issues using the Panel Method within VSPAero when importing a custom airfoil.

I'm using a NACA 25118 airfoil created online from Airfoil Tools and have attempted to force a sharp leading edge in the modify tab. However, when I run the simulation, I get several warnings that say, "These should be the same value if we assume a sensical mesh... but we problably coarsened too much! The solver will likely be fine... but you might want check the coarse meshes if this mesh is actually used..." Finally, at the end, the solver returns the message, "Could not find matching edge!" after which it crashes.

I've included a simple example in this post to see if anyone can recreate my error.

Thanks in advance!

Mike

[Rob McDonald]

I'm seeing the same issue -- can't really figure out why.

It seems like the best solution would be for OpenVSP to support the 5-digit reflex camber lines natively -- that way you wouldn't need to use a file airfoil at all.

Hopefully we can fix it both ways.

I'll keep digging.

Rob

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[Michael Hughes]

Hey Rob,

I think I've found the issue. My original airfoil file was missing a point. I managed to fix that file, which addressed the problem, and was also able to close the airfoil using the Modify tab and enforcing a flat trailing edge instead of a sharp one. Just wanted to follow up in case someone else is having the same issue in the future!

Best,

Michael

[skyc...@gmail.com]

Hello,

For what it's worth, I've been having similar issues due to importing an airfoil file with the finite thickness trailing edge.  I was able to solve by using the "Closure" feature in the modify tab, which closed the TE to a sharp point.  This has also helped when exporting to other panel codes as well, as it makes it easier to define the vortex shedding TE regions.   

Thanks!

Bryan