[Nek5000-users] Vanishing Jacobians while using moving mesh

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

Pradeep,

Start by setting p93-95 to 0 in your .rea file.

I'll look at the rest of your setup today.

Cheers,

Paul


On Tue, 14 Feb 2012, nek5000-users at lists.mcs.anl.gov wrote:

> Hi Neks,
>
> I'm trying to simulate 2D flow over an oscillating cylinder using moving
> mesh, and tried to set up a test case by looking at the peris example. I
> however am getting vanishing Jacobians after the first few timesteps.
>
> I am modifying the the boundary velocity of the cylinder in userbc instead
> of userchk (as in the peris example). Would it be possible for you to look
> at my .usr file and tell me what I am doing wrong?
>
> I have attached the .rea, .usr, and SIZE with this mail.
>
> Further, when I try to view the mesh of the output (or the xyz fld
> outputfile) in visit, visit crashes with the following error:
> VisIt's viewer exited abnormally! Aborting the Graphical User Interface.
>
> Lastly, would it be possible to simulate moving walls with large
> deformations (i.e. where multiple elements get deformed), where the
> deformation is known ahead of time? (eg. a flapping aerofoil)
>
> Thank you for your help!
>
> Regards,
> Pradeep
>
> Extract from logfile:
>
>        60 U-PRES gmres:    100  7.5345E+42  1.0000E-02  4.0062E+57
> 6.7556E-03  1.5093E-02
> ERROR:  alphad .le. 0 in econjp -1.31175831444004495E+179          16
> ERROR:  alphad .le. 0 in econjp -1.31175831444004495E+179          16
> ERROR:  alphad .le. 0 in econjp -1.31175831444004495E+179          16
> ERROR:  alphad .le. 0 in econjp -1.31175831444004495E+179          16
>          60  DNORM, DIVEX  1.18120867781751263E+043
> 7.53448962619089522E+042
>         60   6.0000E-02  1.6697E-02 Fluid done
>     DT/DTCFL/DTFS/DTINIT   0.635E-45   0.635E-45   0.000E+00   0.100E-02
> Step     61, t= 6.0800000E-02, DT= 8.0000000E-04, C=******* 2.2667E-01
> 1.8287E-02
>             Solving for fluid
>
>
>    3  ERROR:  Vanishing Jacobian near      2th node of element         3.
>
>
>    2  ERROR:  Vanishing Jacobian near      2th node of element         1.
>  2.27348348709230109E+081 -5.12478988977734591E+080
> -2.60483379627720531E+079  3.21465902039155941E+039
>    3 xyz:  -5.30056E+39  -5.84642E+39
>    3 xyz:  -5.24850E+39  -6.93109E+39
>
>
>    3  ERROR:  Vanishing Jacobian near      2th node of element         4.
>    2 xyz:   1.25061E+38   4.64957E+39
>  9.79493533554062390E+080 -3.01548938509156252E+080
>    2 xyz:  -2.46589E-08  -5.64092E-01
>
>
>    3 xyz:  -5.30056E+39  -5.84642E+39
>    3 xyz:  -5.24850E+39  -6.93109E+39
>    2  ERROR:  Vanishing Jacobian near      3th node of element         2.
>
>
>    3  ERROR:  Vanishing Jacobian near      2th node of element         5.
>  1.43125817410005932E+039 -6.03607926692375119E+038
>  5.54918579647991880E+039 -1.67302572815141788E+039
>    3 xyz:  -5.30056E+39  -5.84642E+39
>    2 xyz:  -2.46589E-08  -5.64092E-01
>    3 xyz:  -5.24850E+39  -6.93109E+39
>
>
>    3  ERROR:  Vanishing Jacobian near      2th node of element         6.
>    2 xyz:  -3.07794E-08  -7.04112E-01
>
>
>    2  ERROR:  Vanishing Jacobian near      7th node of element         7.
>  8.35923896949543198E+038 -3.55455289325888722E+038
>    3 xyz:  -5.30056E+39  -5.84642E+39
>  1.21747337192549314E+039 -1.79454406120891328E+038
>    3 xyz:  -5.24850E+39  -6.93109E+39
>    2 xyz:  -5.66434E-08  -1.29581E+00
>    2 xyz:  -6.27639E-08  -1.43583E+00
>
>
>    2  ERROR:  Vanishing Jacobian near      9th node of element         8.
>  1.17802538305091326E+039 -4.21489851051369387E+038
>    2 xyz:  -6.55671E-08  -1.49996E+00
>    2 xyz:  -3.25016E+38   4.93026E+39
> call outfld: ifpsco: F
>
>       61  6.0800E-02 Write checkpoint:
>
>       61  6.0800E-02 OPEN:
> xyzcyl2.fld01
>
> Jac error 1, setting p66=4, ifxyo=t
>
> call exitt: dying ...
>