[Nek5000-users] Vanishing Jacobian error description

[nek5000-users at lists.mcs.anl.gov]

Hi Michael,

I get this error when using a too large time step with a moving free
surface problem.  The problem being that the mesh deforms excessively.
Are you working on a moving boundary problem?

Cheers,
Frank 


On Tue, 2010-04-20 at 13:31 -0500, nek5000-users at lists.mcs.anl.gov
wrote:
> Hi,
> 
> I am running into an issue with 'Vanishing Jacobian'.  To help
> understand what the problem
> is, could someone explain what is meant in the error? Specifically,
> what it means by "Xth node" of the element. 
> Also, I ran into this issue when I was deforming geometries in the usr
> file, where one of the elements 
> would overlap another by mistake. However in this case I know there
> are no overlaps. 
> 
> Here is a portion:
> 
>     0  ERROR:  Vanishing Jacobian near     91th node of element
> 69.
>   1.40692804605498586E-002 -7.79619559165757245E-003
>     0 xyz:   2.65874E-01   3.54498E-01   2.87050E+00
>     0 xyz:   2.07855E-01   1.77249E-01   2.87050E+00
> 
> 
>     0  ERROR:  Vanishing Jacobian near     76th node of element
> 70.
>   2.59472856644434001E-002 -2.12442422718029170E-002
>     0 xyz:   2.11655E-01   4.23310E-01   2.62500E+00
>     0 xyz:   3.54498E-01   1.77249E-01   2.87050E+00
> 
> Thanks for any help deciphering this error!
> 
> - Michael
> 
> 
> 
> 
> 
> 
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-- 
Frank Herbert Muldoon, Ph.D. Mechanical Engineering
Technische Universität Wien (Technical University of Vienna)
Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
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