[Gmsh] Higher Order Tools: "Regulerize"

[Zuheyr Alsalihi]

Dear Gmsh Community,

I mysteriously got 1 3D Surface 2 3D volume negative Jacobians in a 2nd 
order, Type C3D10 element 3D solid mesh using curved elements.
Whatever I did I could not remove it. Then I came across an email by 
Prof Geuzaine:


"And to avoid such negative jacobians, you can use the "High order 
tools" (in the Mesh menu). This is still experimental, but works quite 
well. The algorithms are described (in part) in

T. Toulorge, C. Geuzaine, J.-F. Remacle, J. Lambrechts. Robust 
untangling of curvilinear meshes. Journal of Computational Physics 254, 
pp. 8-26, 2013. 
http://gmsh.info/doc/preprints/gmsh_untangling_preprint.pdf"

And indeed, the "Regulerize" button miraculously reported the negative 
volume was optimized.

I just want to know:

if I am correct about this "regularize" and the resulting mesh is indeed 
OK as I was
not able to see the negative volume in 163k elements.

What do you usually do to remove negative volumes?! I tried finer and 
coarser meshes.

Thank you very much for reading!

Best regards,

-- 
Dr. Zuheyr Alsalihi
Senior Research Engineer
Turbomachinery and Propulsion Department
von Karman Institute for Fluid Dynamics
Waterloosesteenweg 72, B-1640 Sint-Genesius-Rode, Belgium
Direct Line: +32 (0)2 359 98 65
Fax: +32 (0)2 359 96 00
E-mail: alsalihi at vki.ac.be
http://www.vki.ac.be