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Please help me about Create one suitable '.cas' file
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TOPIC: Please help me about Create one suitable '.cas' file

Please help me about Create one suitable '.cas' file 12 years 5 months ago #4684

  • saleh
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Hi

I want to simulate a drainage basin with a length of 40 km.
Initial conditions for the 12 mm depth of water throughout the basin considered to have no velocity(Instead of a depth of 12 mm rainfall :huh: ). I am want to continue the simulation until I sure that the peak in the ordinary has happened.
I've attached 'geo.slf' file.
geo.slf

I have used this file but does not work well.Please Help Me :side:
I have given this keyword from the validations and T2D-reference_manual.

/---------------------------------------------------------------------
/ TELEMAC2D Version v6p1 Jun 3, 2012
/ nom inconnu
/---------------------------------------------------------------------




/---------------------------------------------------------------------
/ EQUATIONS
/---------------------------------------------------------------------

FRICTION COEFFICIENT   =30.

LAW OF BOTTOM FRICTION =3

VELOCITY DIFFUSIVITY   =0.000001


/---------------------------------------------------------------------
/ INPUT-OUTPUT, FILES
/---------------------------------------------------------------------

STEERING FILE             ='cas'

BOUNDARY CONDITIONS FILE  ='cas.conlim'

PREVIOUS COMPUTATION FILE ='condInit.ser'

RESULTS FILE              ='results.slf'

GEOMETRY FILE             ='geo.slf'

/---------------------------------------------------------------------
/ INPUT-OUTPUT, GRAPHICS AND LISTING
/---------------------------------------------------------------------

LISTING PRINTOUT PERIOD         =10

VARIABLES FOR GRAPHIC PRINTOUTS =U,V,B,H,Q

GRAPHIC PRINTOUT PERIOD         =10


/---------------------------------------------------------------------
/ INPUT-OUTPUT, INFORMATION
/---------------------------------------------------------------------

COMPUTATION CONTINUED =true


/---------------------------------------------------------------------
/ NUMERICAL PARAMETERS
/---------------------------------------------------------------------

STOP IF A STEADY STATE IS REACHED   =true

NUMBER OF TIME STEPS                =900

FREE SURFACE GRADIENT COMPATIBILITY =1.1

SUPG OPTION                         =1;0

TIME STEP                           =2.0


/---------------------------------------------------------------------
/ NUMERICAL PARAMETERS, SOLVER
/---------------------------------------------------------------------

SOLVER                                  =1

MAXIMUM NUMBER OF ITERATIONS FOR SOLVER =200


/---------------------------------------------------------------------
/ NUMERICAL PARAMETERS, VELOCITY-CELERITY-HIGHT
/---------------------------------------------------------------------

MASS-LUMPING ON H        =1.

MASS-LUMPING ON VELOCITY =1.
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Sorry I did not attach the file with the first topic. 12 years 5 months ago #4685

  • saleh
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Hello again
Sorry I did not attach the file with the first topic.

With best regards,

saleh

File Attachment:

File Name: geo.rar
File Size: 1,470 KB
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Re: Sorry I did not attach the file with the first topic. 12 years 5 months ago #4688

  • c.coulet
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Hi
you wrote it doesn't work but what is the error message?
With such initial condition, maybe the time step is too high?
Another remark
FREE SURFACE GRADIENT COMPATIBILITY should be between 0 and 1 and you give the value 1.1 ...

Regards
Christophe
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Re: Sorry I did not attach the file with the first topic. 12 years 5 months ago #4698

  • saleh
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Hi
sorry
Until the middle are going well but slowly going about an hour (too slowly).
My first try was with a value of 1 and 0.9
(FREE SURFACE GRADIENT COMPATIBILITY .9 & 1).
The last occurrence was 1.1, which was continued calculations longer but the same happening again.
Initial conditions is very little depth in an area with a slope almost too low. What is your recommendation about the appropriate keywords and time step?
This Picture took 1.5 h for:
FREE SURFACE GRADIENT COMPATIBILITY = .9
TIME STEP =2.0

With Best Regards

M.saleh
Attachments:
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Re: Sorry I did not attach the file with the first topic. 12 years 5 months ago #4699

  • c.coulet
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Hi
As your result indicate maximum iteration during the resolution, you should try with lower value of time step.
Two possibilities:
  1. try with 1 or 0.1
  2. try with a variable time step and see the time step use by telemac if the convergence of solver is reached

I'm not sure that the FREE SURFACE GRADIENT COMPATIBILITY is the good keyword to change in your case. The main problem is a time step problem linked to your mesh size and the velocities on small water depth

Hope this helps
Christophe
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Re: Sorry I did not attach the file with the first topic. 12 years 5 months ago #4701

  • saleh
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Hi

Thanks for your quick response.
Is it a good value for Courant number?
DESIRED COURANT NUMBER=.9

Regards

M.Saleh
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Re: Sorry I did not attach the file with the first topic. 12 years 5 months ago #4702

  • c.coulet
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Yes it is. But if it's not sufficient you could try 0.8 or 0.5
If the case has allways problem that could also mean you have a problem with your mesh...

Hope this helps
Christophe
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Re: Sorry I did not attach the file with the first topic. 12 years 5 months ago #4703

  • saleh
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This is true, My mesh have very problem.
I'm trying to correct it.
With Best Regards

M.Saleh
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