Multi-element rear wing for racecar - Failed: Front advance failed

Hello!

I have created a multi element rear wing for a racecar, simply made of two upside-down NACA 4415 airfoils that comes from the 'Flow Over an Airfoil' tutorial (http://www.symscape.com/node/561).

I want to eventually get some velocity and downforce data by following the 'Flow over a CO2 Dragster' tutorial (http://www.symscape.com/node/1082), except by using the wing I've created in place of the dragster model and adjusting accordingly. However I'm having a problem when I try to apply the Vector Fields->U to the wing, as I get the following message:

"Tetulator: End: 2675 tetrahedra
Warning:
flow-volume [www.1289.5] Tetulator: Failed: Front advance failed: 568 faces remain"

I'm assuming this means there's something wrong with the meshing. I have attempted the 'Mesh Diagnostics' guide (http://www.symscape.com/node/995#comment-758) over the course of the past 3 hours but I have to admit I don't understand it very well as I'm new to CFD so I haven't gotten anywhere with regards to fixing the mesh or even finding out what the problem is.

I've tried and tried so posting here really is a last resort, could someone please give me some detailed instructions on what the problem is and how to correct it? It would be much appreciated! I can upload the file or something if that would help. Thanks again!
Ricky

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Single flow volume

Are you sure you have a single flow volume? I.e., did you subtract your airfoils from a large box?

Where you able to view your mesh both on the faces and in the volume?

Did you try using the Accuracy tool to improve your mesh?

For a more complete mesh diagnostics routine see "How do I fix mesh and solver failures?".

Yes I subtracted them from

Yes I subtracted them from the box to get a single flow volume, I was also able to view it on both the faces and the volume.
I had an issue with that however, as when I used the Booleans->Subtract to form the single flow volume roughly half of the length of the leading and trailing edges disappeared, despite having been a full volume previously. After messing with the Unite tool they 'reappeared' again and I continued with the tutorial.

Could this be the root of the problem?

I attempted to follow the "How do I fix mesh and solver failures?" diagnostics and the accuracy tool but it was a little beyond me :/. Thanks for the reply :)

Geometry corrupt

Based on your description it sounds like your geometry is corrupt, i.e., the Booleans->Subtract did not succeed. I don't see how using Booleans->Unite would help.

For Subtract to work you need to ensure that there are no coincident faces or edges. Also are you sure the airfoils are volumes (not just faces) - you extruded faces to form volumes right?

So make sure your airfoil volumes extend beyond the bounds of your box and perform the Subtract. Then check the File->Log for warnings or errors.

Do you have access to a CAD system? If so why not generate the flow volume in it? Then you could exchange the geometry using STEP (.stp).

So I started again from

So I started again from scratch and still had the same problem after the Booleans->Subtract; half of the leading/trailing edges disappeared. They were definitely volumes before this happened (not just faces).

I used the Geometry->Others->Fix tool (not sure why but it looked like it might work) and lo and behold it "fixed" the edges :) So, all's well... but then when I advance to the next step of applying a substance (air) to the volume, the volume is no longer there in the Select dialog - it's just Sim,Faces,Edges,&Vertices with no 'Volume' available for selection.

It seems as if the Fix tool somehow fixed the missing edges but erased the Volume? Haha. Any ideas? Maybe a bug of some kind?
ps: Sadly I don't have any CAD as I'm working from home at the moment.
Thanks again

Fix the volume, not the faces

If you want to preserve the volume then you need to use Others->Fix on the volume, not the faces. Alternatively you can keep your fixed faces and then use the Volumes->Stitch tool to stitch the faces into a volume. After each operation check File->Log for warnings or errors.

Thank you for your

Thank you for your perseverance in helping me with this :)

I'm having no luck with it so I was wondering if it would be possible to somehow isolate/cut-out the rear-wing from the 'Open Wheel Race Car' geometry (http://www.symscape.com/node/130) and maybe copy/paste it into a new simulation and use that rear wing instead of my own airfoil?

Caedium Professional Subscription Purchase

It seems you require dedicated email support to pursue this project, so I think it's time to consider a Caedium Professional 1 year subscription purchase.

I would if I wasn't a student

I would if I wasn't a student who only needs to perform a single simulation. Thanks for the help thus far anyway :)

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