1d/2d modeling Unsteady Flow Analysis error

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1d/2d modeling Unsteady Flow Analysis error

Reylin
I have been trying to run a river model with an applied terrain using Beta 5.0 to only a specific part of a reach. However, the solver has always failed. I tried the instructions regarding the HTab parameters, still it won't work. This time, I reduced the time step to 30 seconds and these were the results.
(I'll try to follow up posting the whole file later.)

And by only a specific part of the model, I mean it like this:


Performing Unsteady Flow Simulation  HEC-RAS 5.0.0 Beta August 2015

Maximum iterations of 20               RS (or Cell) WSEL ERROR

26SEP2009 02:22:30  Marikina River   Upper_marikina_z 23394     22.53   0.020
26SEP2009 05:56:09  Marikina River   Upper_marikina_z 22446.8*   28.65   0.027
26SEP2009 06:00:33  Marikina River   Upper_marikina_z 22696.9*   35.46   0.040
26SEP2009 06:00:39  Marikina River   Upper_marikina_z 21155.0*   27.85   0.020
26SEP2009 06:00:42  Marikina River   Upper_marikina_z 22696.9*   36.34   0.201
26SEP2009 06:00:48  Marikina River   Upper_marikina_z 22512.1*   43.68   0.032
26SEP2009 06:00:51  Marikina River   Upper_marikina_z 22604.5*   36.08   0.993
26SEP2009 06:01:15  Marikina River   Upper_marikina_z 22446.8*   41.88   0.213
26SEP2009 06:01:18  Marikina River   Upper_marikina_z 22604.5*   38.05   1.767
26SEP2009 06:01:21  Marikina River   Upper_marikina_z 21745.*   32.40   0.069
26SEP2009 06:01:33  Marikina River   Upper_marikina_z 22512.1*   47.50   0.173
26SEP2009 06:01:36  Marikina River   Upper_marikina_z 22604.5*   37.83   1.166
26SEP2009 06:01:45  Marikina River   Upper_marikina_z 22604.5*   39.97   1.976
26SEP2009 06:01:51  Marikina River   Upper_marikina_z 22512.1*   49.23   0.107
26SEP2009 06:01:54  Marikina River   Upper_marikina_z 22446.8*   40.14   1.887
26SEP2009 06:02:03  Marikina River   Upper_marikina_z 22604.5*   40.15   1.131
26SEP2009 06:02:06  Marikina River   Upper_marikina_z 22789.2*   40.19   0.292
26SEP2009 06:02:12  Marikina River   Upper_marikina_z 22446.8*   42.87   3.707
26SEP2009 06:02:15  Marikina River   Upper_marikina_z 22120.8*   42.59   0.261
26SEP2009 06:02:21  Marikina River   Upper_marikina_z 22512.1*   44.19   5.319
26SEP2009 06:02:30  Marikina River   Upper_marikina_z 22466     54.45   5.458
26SEP2009 06:02:33  Marikina River   Upper_marikina_z 22512.1*   41.90   0.730
26SEP2009 06:02:39  Marikina River   Upper_marikina_z 22466     63.30   5.612
26SEP2009 06:02:42  Marikina River   Upper_marikina_z 22512.1*   56.68   4.788
26SEP2009 06:02:48  Marikina River   Upper_marikina_z 22512.1*   88.76   6.492
26SEP2009 06:02:51  Marikina River   Upper_marikina_z 22446.8*   71.56   8.311
26SEP2009 06:02:57  Marikina River   Upper_marikina_z 22466    141.03  18.341
26SEP2009 06:03:00  Marikina River   Upper_marikina_z 22512.1*  111.95  13.109
26SEP2009 06:03:06  Marikina River   Upper_marikina_z 22198.2*  318.19  73.182
26SEP2009 06:03:09  Marikina River   Upper_marikina_z 22198.2*  234.20  61.609
26SEP2009 06:03:12  Marikina River   Upper_marikina_z 19973.2*   15.67   0.114
26SEP2009 06:03:15  Marikina River   Upper_marikina_z 19524     24.47  12.407
26SEP2009 06:03:18  Marikina River   Upper_marikina_z 20977.5* 10799.05  35.242

   ****   ERROR:  Solution Solver Failed   ****

Minimum error exceeds allowable tolerance at   26SEP2009   06:03:18

Marikina River   Upper_marikina_z 20453.*

*****  Warning!  Extrapolated above Cross Section Table at:  *****
       (The extrapolation may have been caused by model instability)

    Marikina River Upper_marikina_z    from R.S.   27024  to  26901.6*
    Marikina River Upper_marikina_z    from R.S.   26820  to  20244.8*

*****  Warning!  Extrapolated above/beyond Rating Curve (Bridge/Culvert/etc.)  *****
       (The extrapolation may have been caused by model instability)

    At River   Marikina River      Reach   Upper_marikina_z      R.S.   27619
    At River   Marikina River      Reach   Upper_marikina_z      R.S.   19373


*Note that I also tried adding cross sections. However, after interpolating them, I have to remove almost everything of them since they won't match the said terrain.


Any help would be appreciated. I badly needed this for my project. Thank you, guys.
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Re: 1d/2d modeling Unsteady Flow Analysis error

Afif
Have you finish this problem? I have the similiar problem, and i have changed the Htab parameter until the computation line is close to WSE, but the error still appear. What should i do? Is this caused by the boundary condition or geometry??
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Re: 1d/2d modeling Unsteady Flow Analysis error

tesfay haile tesfay
In reply to this post by Reylin
hi dears i have the same error with all of you? have you ever solution regarding this problem? please share me.
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Re: 1d/2d modeling Unsteady Flow Analysis error

Luis Partida
This is just a common unsteady model error. Either the model is drying out somewhere or the time step is not appropriate. Decrease your time step to something like 1 second and try it out. If not add minimal flow to cross sections with errors in initial conditions