open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,

I have recently downloaded v6p2 and I am getting some problems with a simulation that used to work on the v6p1.

It is a simple rectangular channel, with one grain-size, bedload only, with sisyphe coupled to telemac2d.

The simulation starts well with only the hydrodynamic computation. Then as soon as sisyphe is called (after 10 time steps for instance), I got a message indicating that max bed evolution is infinite on some nodes (usually at the entrance of the channel). The next hydrodynamic computation steps then can not converge ("exceeded number of iterations").

I have tried using very large grain-size that should not move at all, using smaller time-steps, but I still get the same problem.

Have there been some changes in sisyphe v6p2 that can explain it? Has anyone used sispyhe v6p2 and encountered any similar problem? or no problem?

Thank you in advance for your advice or comments,
Caroline

Hi Caroline,
Could you please send us your files to take a closer look or give us little more of details (fortran files, etc.) ?

Regards,
pablo

Hi Pablo,

Thank you for your answer.
Here are the files: that's the simplest case for which I have observed the problem (no fortran file). The sediment size here is very large so no transport should occur, but I had the same problem with all sort of sizes.
Apart from moving from v6p1 to v6p2, I have also changed from the perl-driven system to the python-driven one, but this should not affect the way sisyphe runs, right?

I am just having a look at the document you sent me. Is that the same boundary file that should define both liquid and solid boundary conditions? I find it confusing that LIQBOR is used to define the solid discharge boundary condition, since it is already used to define the liquid boundary. Anyway, I see that in my file, LIEBOR is 2, so I will try to modify it.

Thank you for your help,
Caroline

Hello Caroline,
* Perl or Python are used to define two different installation procedures that don't affect the way in which the modules are running.
* Take care with your EBOR=2 at the inflow boundary. You are blocking the sediment input! Use instead the possibilities presented in the document I sent to you, as well as in the validation folder.

I hope this helps,

all the best

pablo

Hello Caroline,
Please take a look to this short document (this will be available soon at the news v6p2). Recently we have improved the imposition of solid discharge at boundaries. You can also look to the validation sample number 2 (canal_solid_discharge_inflow).

I hope this helps

all the best,

Pablo

Hi Pablo,

Thanks for your comments.

I was actually using LIEBOR=2 to prevent sediments from entering the reach. According to your document, if I have an imposed liquid discharge upstream (LIQBOR=5), the only option for the solid discharge is too let it free with LIEBOR=4, is that right?
In my case, I would like to have an imposed liquid discharge but no sediment input, how should I configure my conlim file to get this?

Thank you for your help,
Caroline

Hi again,

After looking again at the document you sent me, I can see I got confused: LIEBOR=4 corresponds to an imposed solid discharge, is that right?

I still don't understand which part of the conlim file relates to liquid boundary conditions and which part relates to solid boundary conditions, and especially, if solid boundary conditions can be specified independantly of the liquid ones. Can I have an imposed upstream liquid discharge and a free upstream solid discharge together?
Does what is called LIQBOR in this document correspond to the previously named LIUBOR and LIVBOR that were the imposed liquid velocities?

Thanks a lot
Caroline

Hi Caroline, The answer is yes, you need two different limit boundary files, one for Telemac-2d (LIHBOR LIUBOR LIVBOR ...)
one for SISYPHe (LIHBOR not used , LIQBOR, QBOR....LIEBOR EBOR )

LIQBOR=5 (KENT) and LIEBOR=4 (KSORT) for boundaries with prescribed solid discharge.

LIEBOR=5 (KENT) and LIQBOR=4 (KSORT) for boundaries with prescribed variation of elevation.

I hope this makes sense, good luck, Cath