open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello everyone,
I would need your help about an error I get running Telemac2D.
I'm working on an italian river (about 2 km2 area) and I'm trying to simulate a steady state event.
I built the geometry file, the boundary condition file and the input sections with BlueKenue.
The mesh seems to be very fine, indeed the geometry file is quite heavy, about 10 Mb.
When I run the simulation this is what is shown:


LISTING OF TELEMAC-2D

---

TTTTT EEEEE L EEEEE M M AAAAA CCCCC
T E L E MM MM A A C
T EEE L EEE M M M AAAAA C
T E L E M M A A C
T EEEEE LLLLL EEEEE M M A A CCCCC

2D VERSION 6.3 FORTRAN 90
WITH SEVERAL TRACERS
COUPLED WITH SISYPHE AND TOMAWAC

********************************************
* LECDON: *
* AFTER CALLING DAMOCLES *
* CHECKING OF DATA READ *
* IN THE STEERING FILE *
********************************************

EXITING LECDON. NAME OF THE STUDY:

OPENING FILES FOR TELEMAC2D

*****************************
* MEMORY ORGANIZATION *
*****************************

READGEO1: TITLE= newSelafin
NUMBER OF ELEMENTS: 525896
NUMBER OF POINTS: 264552

FORMAT NOT INDICATED IN TITLE

MXPTEL (BIEF) : MAXIMUM NUMBER OF ELEMENTS AROUND A POINT: 9
MAXIMUM NUMBER OF POINTS AROUND A POINT: 9
CORRXY (BIEF):NO MODIFICATION OF COORDINATES

MESH: MESH ALLOCATED
POINT_TELEMAC2D: SECTIONS DEFINED IN THE SECTIONS INPUT FILE

*************************************
* END OF MEMORY ORGANIZATION: *
*************************************

CALLING LECLIM
BACK FROM LECLIM
CALLING INBIEF
INBIEF (BIEF): NOT A VECTOR MACHINE (ACCORDING TO YOUR DATA)
GEOELT: ELEMENT 15313 : NEGATIVE DETERMINANT


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

... handling result files

+> bisagno7.cas
moving: sections_output
moving: results7.txt


My work is done
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



I know that there are other topics about the problem "negative determinant" but they haven't helped me to fix the problem so far.


Thank you in advance for your support

Daniele

Hi

This is a problem linked to a wrong mesh.
Have a look on the wrong element. It should be probably flat...
Take care about the precision of the coordinates

Hope this helps

Thank you c.coulet for your reply.
Actually I don't see nothing wrong in my mesh, I attach the geometry file in case you want to have a look.
how can I choose the precision of the coordinates?

thank you again
Daniele

the geometry file probably is too big to be attached, so I quickly describe you the procedure I made to create the mesh in BK.

1) I used, as initial file, a xyz file
2) I drew the left and right banks using an open line
3) with a closed line I drew the domain
4) because the points in the domain weren't so many, I use the "resample" option and modified it with the "maximum distance method" and "delta=1".
5) then I run the T3channel mesh (parameters: cross channel node count = 100, along channel interval =1 )
6) I created the t3 mesh generator, dragging the domain and the t3channel mesh respectly to "outline" and "submeshes"
7) I run the simulation with: "resample Outline" and resample line only unselected, a defaultedge length =1.
8) after the interpolation with the xyz file the mesh seems to be very good, but evidently I did some mistakes :)


I hope this can help you to help me :)

thanks again

Daniele

Hi
You can't choose the precision but the selafin file format force the coordinates to be simple precision real so only 7 significants numbers.

Maybe you could have a look in the mesh informations in BK because the description of the procedure isn't sufficient to judge it.

Regards

thank you c.coulet. I'll have a better look :) In the meantime I attach the file with the information of the mesh, it can probably help to identify the problem.
Thank you again
Regards

Daniele

Hi

As i supposed, you have a flat element in your model
The mesh information gives:
Minimum Element Area: 0.000000

Try to find the element from its number (15313)

Regards

I don't notice nothing wrong in this element. I attach a picture of it



By the way, I created an hardline around this point and then run another mesh.
Finally telemac found the same previous problem but for another element:
CALLING LECLIM
BACK FROM LECLIM
CALLING INBIEF
INBIEF (BIEF): NOT A VECTOR MACHINE (ACCORDING TO YOUR DATA)
GEOELT: ELEMENT 15319 : NEGATIVE DETERMINANT


Regards

It seems logical as you look on a node and not on an element!

By the may, as your coordinates on Y are > 1 000 000, and as I already wrote before, the precision problem force the selafin file to round the coordinates.

Try to open the geometry file (selafin) instead the mesh result and you will probably see some differences when you zoom in

Regards

Thank you so much, I've translated the Y coordinates and it works now!

best regards

Daniele