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TOPIC: sediment transport formula

sediment transport formula 9 years 2 months ago #18311

  • river
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Hello to all

Please I‘d run a simulation with a two different zones (different characteristic of sediment) so I want to use different sediment formula, in the two zones (for example Van Rijn in the first zone and MP in second zone …) is that possible? If yes how can I do that? I know, it is possible to define two zones with different roughness law, but for two different sediment transport formula, I didn’t’ see that in the user manual ???

Someone have an idea about that please
Thank you in advance
Jean
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sediment transport formula 9 years 2 months ago #18312

  • jmhervouet
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Hello,

No, this has not been done yet in Sisyphe. If you already have the zones in Telemac-2D, a quick and dirty solution would be to change one of the subroutines in Sisyphe corresponding to 1 transport formula, and to change it, adding the command USE DECLARATIONS_TELEMAC2D, ONLY : ZONES,NZONE

Then you can apply different laws by looking at the value of ZONE%I(I) for a point I in the mesh.

This cannot be done in a clean solution because Sisyphe may be compiled without Telemac-2D.

With best regards,

Jean-Michel Hervouet
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sediment transport formula 9 years 2 months ago #18314

  • river
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HELLO JMH

thank you so much for your reply!! sure that's will help me, but please can you explain more how can I apply different laws by looking at the falue of zone ( how can I add that in the subroutine)

because I have defined two zones with two different rougness law ( Zone1=1 and Zone 2=2), If I understand well your Idea, I should add in each subroutine of the transport formula that I want to use in each zone DECLARATIONS_TELEMAC2D, ONLY : ZONES,NZONE, then, (apply different laws by looking at the value of ZONE%I(I) for a point I in the mesh) this I didn't understand very well, how can I add that in the subroutine if I have define zone 1 and zone 2 and I'd applty for exemple the formula of MP in zone 1 and the formula of Van Rijn in Zone 2 and what I write in the sisyphe steering file to define the formula ??
thank you in advance

Jean
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sediment transport formula 9 years 2 months ago #18324

  • jmhervouet
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Hello,

After discussing with specialists here, they strongly advise that you should not do so. I also came to the conclusion that if you mix two formulas, the difference between them will do a divergence of the bedload vector at the interface between laws, that will trigger either artificial erosion or artificial deposition. Given the uncertainties, it is better to calibrate your case with one law. You can also design your own user law and choose an average between two laws.

With best regards,

Jean-Michel Hervouet
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sediment transport formula 9 years 2 months ago #18325

  • river
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HI

thank you for your reply and your suggestions, I'll try so to calibrate some parameters and use one law

best regards
Jean
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sediment transport formula 9 years 2 months ago #18330

  • river
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Hi

Sorry, just a question, I defined a new formula that can be used to calculate sediment transport in th two zones but I use two different coefficient of calibaration in each zone and I use Qsform to define my formula
QSC%R(N) = C1 * T zone 1 and QSC%R(N) = C2 * T
the problem in the defintion of node
I can do for exemple if ((N.eq.1778).or.(N.eq.1779)) then
QSC%R(N) = C1 * T
else
QSC%R(N) = C2 * T
but I have a big number of nodes I prefer to use the Zone ( in which I defined in the defintion of friction law )
how can I use that for exemple I'd like
for zone =1 QSC%R(N) = C1 * T
for zone =2 QSC%R(N) = C2 * T

thank you in advance
Jean
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sediment transport formula 9 years 2 months ago #18331

  • jmhervouet
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Hello,

So it is :

USE DECLARATIONS_TELEMAC2D, ONLY : ZONES

...

IF(ZONES%I(I).EQ.1) THEN
...
ELSE
...
ENDIF

Regards,

JMH
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sediment transport formula 9 years 2 months ago #18336

  • river
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Hello
thank you so much
I use this expression because we have NZONES in telemac 2D

IF(NZONES%R(N).EQ.1) THEN....
but I find this error
Error: Syntax error in IF-expression at (1)
t2dfort.f:1713.132:

Error: Unexpected ELSE statement at (1)
t2dfort.f:1715.11:

I didn't understand where is the problem ??
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sediment transport formula 9 years 2 months ago #18338

  • jmhervouet
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Hello,

NZONES is the number of zones (integer), then ZONES tells you the zone number, so:

IF(ZONES%I(N).EQ.1) THEN....

Regards,

JMH
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sediment transport formula 9 years 2 months ago #18339

  • river
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USE DECLARATIONS_TELEMAC2D, ONLY : ZONES
1
Hello
the problem that zones not found in module declarations telemac 2D mybe be cause I used V6p2 ???

Error: Symbol 'zones' referenced at (1) not found in module 'declarations_telema
c2d'
t2dfort.f:1676.21:

IF(ZONES%R(N).EQ.2) THEN
1
Error: Syntax error in IF-expression at (1)
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