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3 D mini element

+2 votes

Hi Everyone
In 3D case, I implemented the Mini element for Stokes like this

P1 = VectorElement("CG", tetrahedron,  1)
B = VectorElement("Bubble", tetrahedron, 4)
Mini = P1 + B

But, the pressure seems unstable. Is the bubble element incorrect? Any comment are appreciated.

asked Aug 14, 2015 by Guodong Zhang FEniCS Novice (420 points)

What do you mean by 'seems unstable'? Did you check the error or can you post a plot of the exact vs. the computed solution?

commented Aug 15, 2015 by Christian Waluga FEniCS Expert (12,310 points)
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