[MITgcm-support] nTimeStep

Jody Klymak jklymak at uvic.ca
Fri Jun 9 12:22:59 EDT 2017


You still haven’t told us what the CFL criteria is in STDOUT.  You may 
need to make `monitorFreq` lower to get the monitor output.  Best to set 
this to the same value as deltaT until you find the problem.  Its also a 
good idea to save every model timestep so you can see where in the 
domain the model is blowing up.  That is often a good clue.

Good luck.  Jody



On 9 Jun 2017, at 8:38, smaeilpour wrote:

> My data file is as:
>
>  viscAz=1.E-3,
>  viscAh=1.E-2,
>  no_slip_sides=.FALSE.,
>  no_slip_bottom=.TRUE.,
>  diffKhT=1.E-2
>  diffKzT=1.E-3,
>  f0=0.00002,
>  beta=2.4228E-11,
>  eosType='LINEAR',
>  tAlpha=2.E-4,
>  sBeta =0.E-4,
>  gravity=9.81,
>  implicitFreeSurface=.TRUE.,
>  exactConserv=.TRUE.
>  nonHydrostatic=.FALSE.,
>  hFacMin=0.2,
>  implicSurfPress=0.5,
>  implicDiv2DFlow=0.5,
>  nonlinFreeSurf=3,
>  hFacInf=0.2,
>  hFacSup=1.8,
>  saltStepping=.TRUE.,
>
> But in STDOUT I have:
>
> (PID.TID 0000.0001) hFacMin =   /* minimum partial cell factor (hFac) 
> */
> (PID.TID 0000.0001)                 2.000000000000000E-01
> (PID.TID 0000.0001)     ;
> (PID.TID 0000.0001) hFacMinDr = /* minimum partial cell thickness ( m) 
> */
> (PID.TID 0000.0001)                 0.000000000000000E+00
>
> after a while of run:
>
> EXTERNAL_FIELDS_LOAD,      1850 : iP,iLd,i0,i1=   12    1   12    1 ; 
> Wght=  0.4964313272  0.5035686728
>  cg2d: Sum(rhs),rhsMax =  NaN                   Infinity
>  EXTERNAL_FIELDS_LOAD,      1851 : iP,iLd,i0,i1=   12    1   12    1 ; 
> Wght=  0.4964293981  0.5035706019
>  cg2d: Sum(rhs),rhsMax =  NaN                    0.00000000000000E+00
>
>
> Cheers,
> Saeid
>
>
>
>
>
>
>
> --------------------------------------------
> On Fri, 6/9/17, Jody Klymak <jklymak at uvic.ca> wrote:
>
>  Subject: Re: [MITgcm-support] nTimeStep
>  To: mitgcm-support at mitgcm.org
>  Date: Friday, June 9, 2017, 11:09 AM
>
>
>  What did STDOUT say?  What is
>  your value of hFac min?
>  Cheers,  Jody
>
>  On 9 Jun 2017, at 8:02, smaeilpour
>  wrote:
>  Thank you Jody,
>
>  I restarted with a deltaT=5, that is small as following:
>
>
>
>  startTime=0,
>
>  endTime=86400,
>
>  deltaT=5,
>
>
>
>  but Model after a while (about 1500 of nTimeStep) becomes
>  unstable, what solution else do you offer except that? and
>  what CFL criteria else should i consider for it?
>
>
>
>  Thank you again,
>
>  Saeid
>
>
>
>
>
>
>
>  --------------------------------------------
>
>  On Wed, 6/7/17, Jody Klymak <jklymak at uvic.ca>
>  wrote:
>
>
>
>   Subject: Re: [MITgcm-support] nTimeStep
>
>   To: mitgcm-support at mitgcm.org
>
>   Date: Wednesday, June 7, 2017, 12:26 PM
>
>
>
>
>
>
>
>   9 times out of 10 you will get this if deltaT is too
>
>   large.  Look for advcfl_*_max in
>
>   STDOUT.0000.  They should be less than one, and
>
>   preferably less than 0.5. A couple of things to be aware
>  of
>
>
>
>
>
>   setting hFacMin to be too
>
>   small value can mean your vertical cell is very small,
>  and
>
>   the CFL
>
>   condition becomes impossible to meet.  hFacMin
>
>   is the fraction of dR that a cell is allowed to
>
>   be near the bottom, so dR=10 m and
>
>   hFacMin=0.1 means the cell can be as thin as 1
>
>   m. If your deltaT=50 then W
>
>   can’t exceed 2 cm/s in that cell.  If the topography
>  is
>
>   steep that is not a gigantic value for W near
>
>   topography.you may have strong start-up
>
>   transients in your solution that make the model behave
>  more
>
>   violently at the start than after it has been allowed to
>
>   evolve.  So check STDOUT.0000 and if the CFL
>
>   criteria starts to drop again, you may be able to
>  restart
>
>   with a smaller deltaT.
>
>
>
>
>
>   Good luck,  Jody
>
>
>
>   On 7 Jun 2017, at 8:35,
>
>   smaeilpour wrote:
>
>
>
>
>
>   Hi everyone,
>
>
>
>   I am trying to run Internal wave, my bathymetry file is
>
>   2160*876 and precision 30s. I'd like to run it in 38
>
>   layer and by 3500m depth. The Model with nTimeStep=100
>  would
>
>   be run well but whenever I increase it for more times I
>
>   encounter with the following error:
>
>
>
>
>
>
>
>   ABNORMAL END: S/R MON_SOLUTION, stops due to EXTREME
>
>   Pot.Temp
>
>
>
>
>
>
>
>   My error in STDER.0000 is:
>
>
>
>   (PID.TID 0000.0001) SOLUTION IS HEADING OUT OF BOUNDS:
>
>   tMin,tMax=-1.918+101  1.617+101
>
>
>
>   (PID.TID 0000.0001)  exceeds allowed range
>
>   (monSolutionMaxRange= 1.000E+03)
>
>
>
>   (PID.TID 0000.0001) MON_SOLUTION: STOPPING CALCULATION
>  at
>
>   Iter=  20
>
>
>
>   (PID.TID 0000.0001) ***ERROR***S/R ALL_PROC_DIE: ending
>  the
>
>   run
>
>
>
>
>
>
>
>   Of course, once I used startTime and endTime instead of
>
>   nTimeStep but it didn't matter.
>
>
>
>
>
>
>
>   My data file is as following:
>
>
>
>    nIter0=0,
>
>
>
>    nTimeSteps=8640,
>
>
>
>    deltaT=50,
>
>
>
>    dumpFreq=21600,
>
>
>
>    pChkptFreq=0,
>
>
>
>    chkptFreq=0,
>
>
>
>    monitorFreq=2500.,
>
>
>
>    periodicExternalForcing=.TRUE.,
>
>
>
>    externForcingPeriod=2592000.,
>
>
>
>    externForcingCycle=31104000.,
>
>
>
>    tauThetaClimRelax=31104000.,
>
>
>
>    abEps=0.02,
>
>
>
>    &
>
>
>
>
>
>
>
>   Is it possible that my domain is big for internal wave
>
>   analysis that I get that error? if not so, how can I fix
>
>   this problem? how can I run model for 4 years and more
>  with
>
>   this situation?
>
>
>
>
>
>
>
>   Thank you in advance for any help,
>
>
>
>   Saeid
>
>
>
>
>
>
>
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>
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>
>
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>
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>
>
>
>
>
>
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