HEC RAS 1D-2D

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HEC RAS 1D-2D

Antoine
Hi I am currently working on the 1D-2D model on Hec RAS. When the simulation ends, I have this error. Someone can help me ? However, I linked my 1D area to 2D with lateral structures

*****  Warning!  Extrapolated above Cross Section Table at:  *****

    TORRAS TORRAS    from R.S.   1967.766  to  554.4768
    TORRAS TORRAS    from R.S.   171.1987  to  13.84495

 

The maximum xsec wsel error was    84.625
TORRAS  TORRAS  1662.188  at  14MAY2018 00:21:32

   ****   The Model Has One Or More Warning(s)   ****

Finished Unsteady Flow Simulation
 
Writing Results to DSS
Finished Writing Results to DSS

Reading Data for Post Process
       
Running Post Processor  HEC-RAS 5.0.3 September 2016

Finished Post Processing


Computations Summary

Computation Task Time(hh:mm:ss)
Completing Geometry       1
Preprocessing Geometry(64) <1
Unsteady Flow Computations(64)    5:51
Writing to DSS(64) <1
Post-Processing(64)       2
Complete Process    5:57
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Re: HEC RAS 1D-2D

Antoine
Now i have this error :

*****  Warning!  Extrapolated above Cross Section Table at:  *****

    TORRAS TORRAS    R.S.   1967.766
    TORRAS TORRAS    from R.S.   1861.708  to  1740.744
    TORRAS TORRAS    from R.S.   1687.615  to  1463.601
    TORRAS TORRAS    from R.S.   308.4406  to  13.84495

 

The maximum xsec wsel error was    17.848
TORRAS  TORRAS  1635.161  at  14MAY2018 01:15:46

   ****   The Model Has One Or More Warning(s)   ****

Finished Unsteady Flow Simulation
 
Writing Results to DSS
Finished Writing Results to DSS

Reading Data for Post Process
       
Running Post Processor  HEC-RAS 5.0.3 September 2016

Finished Post Processing


Computations Summary

Computation Task Time(hh:mm:ss)
Completing Geometry       1
Preprocessing Geometry(64) <1
Unsteady Flow Computations(64)    2:03
Writing to DSS(64) <1
Post-Processing(64)       3
Complete Process    2:09
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Re: HEC RAS 1D-2D

cameron
This basically means your model is going unstable or it means your 1D htab parameters need to be adjusted.

You may need to lower your timestep or turn on the 1D/2D iteration option.
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Re: HEC RAS 1D-2D

Antoine
Hello Cameron, I restarted my model this morning trying to adjust the option of iteration 1D / 2D on 20.
Even by modifying my Htab (copy invert) and trying to change my time step I still have the same error. An idea ?

*****  Warning!  Extrapolated above Cross Section Table at:  *****

    TORRAS TORRAS    R.S.   1967.766
    TORRAS TORRAS    from R.S.   1861.708  to  1847.852
    TORRAS TORRAS    from R.S.   1740.744  to  1635.161
    TORRAS TORRAS    from R.S.   1608.497  to  1498.896
    TORRAS TORRAS    from R.S.   209.7826  to  13.84495

 

The maximum xsec wsel error was     6.153
TORRAS  TORRAS  388.5036  at  14MAY2018 00:18:56

   ****   The Model Has One Or More Warning(s)   ****

Finished Unsteady Flow Simulation
 
Writing Results to DSS
Finished Writing Results to DSS

Reading Data for Post Process
       
Running Post Processor  HEC-RAS 5.0.3 September 2016

Finished Post Processing


Computations Summary

Computation Task Time(hh:mm:ss)
Completing Geometry       1
Preprocessing Geometry(64) <1
Unsteady Flow Computations(64)    2:17
Writing to DSS(64) <1
Post-Processing(64)       9
Complete Process    2:29
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Re: HEC RAS 1D-2D

Antoine
My 1D zone works fine, however, when I try to connect my 2D zone to my 1D zone with a side structure, the simulation contains errors ... help?
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Re: HEC RAS 1D-2D

cameron
what is your time step?
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Re: HEC RAS 1D-2D

Antoine
During my modeling I use the following parameters :

Starting date : 14 MAY 2018
Starting time : 0000
Ending date : 14 MAY 2018
Ending time : 0300
Computation Interval : 2 seconds
Mapping Output Interval : 1 minute
Hydrograph Output Interval : 6 minutes
Detailed Output Interval : 6 minutes

Options and Tolerances :
Maximum iterations between 1D and 2D : 1
Water surface tolerance (m) : 0.01
Flow tolerance (%) : 0.1
Minimum flow tolerance (m3/s) : 0.003

Thanks for your reply !
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Re: HEC RAS 1D-2D

cameron
set the max 1D/2D iterations to 20.

What is the weir coefficient you are using for the lateral structure? Did you try setting it to use 2D equation instead of weir?

This all only applies if the issues are near the 1D/2D connection.  
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Re: HEC RAS 1D-2D

Antoine
For now I use this coefficient for the lateral structure: 0.8
I tried using 1.1 and it works, I have no error stream
But I still have the same error and I don't know how it can be solved

*****  Warning!  Extrapolated above Cross Section Table at:  *****

    TORRAS TORRAS    from R.S.   1967.766  to  1847.852
    TORRAS TORRAS    R.S.   1740.744
    TORRAS TORRAS    R.S.   1687.615
    TORRAS TORRAS    R.S.   1641.775
    TORRAS TORRAS    R.S.   1608.497
    TORRAS TORRAS    R.S.   139.8516
    TORRAS TORRAS    from R.S.   101.1404  to  13.84495

 

The maximum xsec wsel error was     4.354
TORRAS  TORRAS  56.40127  at  14MAY2018 02:38:18

   ****   The Model Has One Or More Warning(s)   ****

Finished Unsteady Flow Simulation
 
Writing Results to DSS
Finished Writing Results to DSS

Reading Data for Post Process
       
Running Post Processor  HEC-RAS 5.0.3 September 2016

Finished Post Processing


Computations Summary

Computation Task Time(hh:mm:ss)
Completing Geometry <1
Preprocessing Geometry(64) <1
Unsteady Flow Computations(64)      29
Writing to DSS(64) <1
Post-Processing(64)       2
Complete Process      35
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Re: HEC RAS 1D-2D

Angie
In reply to this post by Antoine
I have built a combined 1D 2D model of a single stretch of river but by combining channela and terrain data for 2D area creation. But, the flow occurs in places beyond the 2D boundary area. Can anyone tell me the reason? thanks in advance.