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TOPIC: Problem in simulating dam using Telemac 3D

Problem in simulating dam using Telemac 3D 9 years 5 months ago #17195

  • jmhervouet
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Hello,

The principle when coupling Telemac-3D and Sisyphe is that the suspension is done by Telemac-3D and the bed-load by Sisyphe. So I am surprised that here in Telemac-3D you have declared no sediment. You should at least have:

NUMBER OF TRACERS : 1 SEDIMENT : YES

So you are probably in a configuration that cannot work and we should issue a message saying that you need to have sediment in Telemac-3D.

You can inspire from the example depot, which does suspension + coupling with Sosyphe.

With best regards,

Jean-Michel Hervouet
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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17203

  • amanj2013
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Hello dear Jean-Michel Hervouet,

In my case I assumed to have only bedload as I did with my model in Telemac2D and Sisyphe. I would like to ask even if I dont consider to have suspended sediment, do I have to still activate sediment option in Telemac3D?

Sincerely,
AMANJ
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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17204

  • amanj2013
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Hello dear Jean-Michel Hervouet,

In my case I assumed to have only bedload as I did with my model in Telemac2D and Sisyphe. I would like to ask even if I dont consider to have suspended sediment, do I have to still activate sediment option in Telemac3D?
By the way, I edit the number of tracer into 1; however, I dont have access to modify sediment to yes as shown in enclosed pictures.

Sincerely,
AMANJ
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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17205

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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17209

  • jmhervouet
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Hello,

OK, I see, yes it should be possible to do that, only bedload in Sisyphe with friction velocity given by Telemac-3D. I'll ask my colleagues for confirmation and apparently there is no test case doing this. If it is correct to do so I do not really know what happens, probably it is linked with tidal flats or very shallow zones.

If you have trouble for changing a keyword, you can always edit the steering file with an editor, and add the keyword where you want.

With best regards,

Jean-Michel Hervouet
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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17226

  • konsonaut
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Hello,

reading the forum posts I can confirm the observations of Amanj. Last year at the User Club I presented some 2D numerical modelling of dam-break, see the proceedings, p.51, in
www.opentelemac.org/index.php/binaries/s...nce-2014-proceedings

So at that time I was curious and tried to simulate the case with Telemac-3D & Sisyphe.
However I had no chance to get stable simulations. I varied some suspect Telemac-3D keywords which could be the reason for the instabilities but after a while I gave it up. But, maybe I just didn't find the right keyword? I'm not that expert in Telemac-3D.

Actually the Telemac-2D inc. Sisyphe case can be downloaded here:

www.opentelemac.org/index.php/kunena/16-...d?limitstart=0#14295

I consider it as exciting to simulate 3D RANS and sediment transport of a dam-break, so I want to propose a deal:
if someone can port the case to Telemac-3D and run a stable AND water depth oscillating-free simulation, I will spend a good bottle of wine (presumably from Northern Italy) at the next user club :-)

Best regards,
Clemens
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The following user(s) said Thank You: amanj2013

Problem in simulating dam using Telemac 3D 9 years 5 months ago #17227

  • amanj2013
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Hello,
Actually I tried and changed by typing in the steering files, but still I have problem of instabilities in the hydrodynamic model. As I mentioned before, I tried only hydrodynamic model without sediment and works very well; however, when coupling with sisyphe, the instability issue is arising at the vicinity of the upstream crest of the dam where the predefined water level reach to the dry zone. As you mentioned, probably the problem is related to either tidal flat ( dry zone) while when I tried without sediment it still working without problem, or related to some parameter between sisyphe and Telemac 3D. Yes dear Clemens, your right, I tried and spent a very good time on solving this issue, but still remains unsolved. I hope someone can help with this issue and the picture as well video I posted will help to figure-out.

Thanks,
AMANJ
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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17246

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Hello dear Jean-Michel Hervouet and Clemens,

I think I am approaching of solving the problem. Now I am running the model again by coupling Telemac3D with Sisyphe the one had problem before. Now I just checked the bed roughness prediction with bed roughness prediction option one and the model is look like stable up to know; however, it may needs couple days to finish. The model didnt work with Option 2 and gave error.

Cheers,
AMANJ
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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17248

  • jmhervouet
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hello,

Good job! This option adds non linearity in the process. The other point to improve needs some programming and will be done in the next version: the friction velocity is infinite on dry zones to cancel the velocities, this is not good if Sisyphe uses this friction velocity for erosion, so we need to have 2 friction velocities, the one for sediment being cancelled near dry zones, or e.g. when the depth is less than the grain size.

With best regards,

Jean-Michel Hervouet
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Problem in simulating dam using Telemac 3D 9 years 5 months ago #17254

  • amanj2013
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Thank you dear Jean-Michel Hervouet,

In regards to our subject, I have a question. Does Sisyphe still get the value of bed shear stress from Telemac 3D since we activated bed roughness predictor or not? In case of having logarithmic law for velocity profile, does telemac 3D share bed shear velocity with sisyphe?

I think we gonna share Clemens WINE together ;)
Sincerely,
AMANJ
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