[MITgcm-support] Non-linear free-surface and vertical resolution
Chun-Yan Zhou
c.zhou at dundee.ac.uk
Fri Sep 7 12:44:47 EDT 2012
Hi all,
In my case the the amplitude of the free-surface variations(tide elevation) becomes as large as the vertical resolution near the surface, and has the following warnings:
WARNING: hFac < hFacInf near: i,j,k,bi,bj,Thid,Iter= 49 2 1 1 1 1 0
hFac_n-1,hFac_n,eta = 1.000000 0.637263 -1.088210E+00
WARNING: hFac < hFacInf near: i,j,k,bi,bj,Thid,Iter= 48 2 1 1 1 1 1
hFac_n-1,hFac_n,eta = 0.866667 0.647780 -1.056660E+00
WARNING: hFac < hFacInf near: i,j,k,bi,bj,Thid,Iter= 49 2 1 1 1 1 1
hFac_n-1,hFac_n,eta = 0.866667 0.635711 -1.092868E+00
when I set the hFacInf=0.1 or smaller, the model will overflow.
http://mitgcm.org/public/r2_manual/latest/online_documents/node42.html
in the manual 2.10.2.5 Non-linear free-surface and vertical resolution, it mentioned that
A better alternative to the vanishing level problem has been found and implemented recently, and rely on a different vertical coordinate r*.
Is there any example or description to show how to use this better alternative ways?
Any suggestion is highly appreciated!
# ====================
# | Model parameters |
# ====================
#
# Continuous equation parameters
&PARM01
viscAh=1.E2,
viscAz=1.E-3,
no_slip_sides=.TRUE.,
no_slip_bottom=.TRUE.,
viscC2Smag=2.0,
viscAhGridMax=0.5,
implicitViscosity=.TRUE.,
implicitDiffusion=.TRUE.,
diffKhT=1.E2,
diffKzT=1.E-3,
diffKhS=0.E2,
diffKzS=0.E-5,
tAlpha=2.E-4,
sBeta =0.,
gravity=9.81,
eosType='LINEAR',
tempStepping=.FALSE.,
saltStepping=.FALSE.,
implicSurfPress=0.5,
implicDiv2DFlow=0.5,
rigidLid=.FALSE.,
implicitFreeSurface=.TRUE.,
readBinaryPrec=64,
writeBinaryPrec=32,
hFacMin=0.05,
nonlinFreeSurf=4,
hFacInf=0.2,
exactConserv=.TRUE.,
&
# Elliptic solver parameters
&PARM02
cg2dMaxIters=1000,
cg2dTargetResidual=1.E-13,
&
# Time stepping parameters
&PARM03
nIter0=0,
nTimeSteps=21600,
deltaT=20,
deltaTtracer=20,
cAdjFreq=0.,
abEps=0.02,
pChkptFreq=432000,
chkptFreq=0.0,
#dumpFreq=7200.0,
dumpFreq=3600,
#taveFreq=86400.0,
monitorFreq=36000.,
# periodicExternalForcing=.TRUE.,
# externForcingPeriod=2592000,
# externForcingCycle=31104000,
pickupStrictlyMatch=.FALSE.,
&
# Gridding parameters
&PARM04
#constant delZ= 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140.,
#variable
usingSphericalPolarGrid=.TRUE.,
delX=174*0.0625,
delY=226*0.0625,
delZ=10*3.,10*7.,10*25.,5*100.,5*180.,
ygOrigin=27.03125,
xgOrigin=117.46875,
&
# Input datasets
&PARM05
bathyFile='topognew1.bin',
uVelInitFile='UVEL200201.bin',
vVelInitFile='VVEL200201.bin',
pSurfInitFile='initeta.bin'
&
Chunyan Zhou
Division of Civil Engineering
School of Engineering, Physics and Mathematics
College of Art, Science and Engineering
Fulton Building,G19
University of Dundee
Dundee, UK DD1 4HN
Tel. 01382 385431
________________________________________
From: mitgcm-support-request at mitgcm.org [mitgcm-support-request at mitgcm.org]
Sent: 05 September 2012 17:00
To: mitgcm-support at mitgcm.org
Subject: MITgcm-support Digest, Vol 111, Issue 7
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Today's Topics:
1. Re: nonlinFreeSurf=4 casue flow field change a lot (Martin Losch)
----------------------------------------------------------------------
Message: 1
Date: Wed, 05 Sep 2012 08:57:28 +0200
From: Martin Losch <Martin.Losch at awi.de>
To: mitgcm-support at mitgcm.org
Subject: Re: [MITgcm-support] nonlinFreeSurf=4 casue flow field change
a lot
Message-ID: <1E2B6C25-BE94-429D-A7DD-AE1AB46E5C7F at awi.de>
Content-Type: text/plain; CHARSET=US-ASCII
The default boundary value for ETAN is zero. For the linear free surface, this value is not used, but for the non-linear free-surface it is, so that you specify ETAN=0 along with your u and v velocities. You might want to add ETAN boundary values that are consistent with your normal boundary velocities (say from integrating geostrophy deta/dx = f/g * v)
M.
On Sep 5, 2012, at 12:11 AM, Chun-Yan Zhou wrote:
> Hi all,
> I did two cases of the regional without and with nonlinFreeSurf=4.
> The model has south and east boundary,driven by boundary u v velocity.
> The result of case without nonlinFreeSurf seems reasonable, with all the conditions stay same except adding nonlinFreeSurf =4, the result change a lot, especially the flow direction in the southeast corner of the model(see the picture attached).
>
> Can anyone tell me where is the problem? Thanks a lot.
>
> # ====================
> # | Model parameters |
> # ====================
> #
> # Continuous equation parameters
> &PARM01
> viscAh=1.E2,
> viscAz=1.E-3,
> no_slip_sides=.TRUE.,
> no_slip_bottom=.TRUE.,
> viscC2Smag=2.0,
> viscAhGridMax=0.5,
> implicitViscosity=.TRUE.,
> implicitDiffusion=.TRUE.,
> diffKhT=1.E2,
> diffKzT=1.E-3,
> diffKhS=0.E2,
> diffKzS=0.E-5,
> tAlpha=2.E-4,
> sBeta =0.,
> gravity=9.81,
> eosType='LINEAR',
> tempStepping=.FALSE.,
> saltStepping=.FALSE.,
> implicSurfPress=0.5,
> implicDiv2DFlow=0.5,
> rigidLid=.FALSE.,
> implicitFreeSurface=.TRUE.,
> readBinaryPrec=64,
> writeBinaryPrec=32,
> hFacMin=0.05,
> nonlinFreeSurf=4,
> hFacInf=0.2,
> hFacSup=2.,
> exactConserv=.TRUE.,
> &
>
> # Elliptic solver parameters
> &PARM02
> cg2dMaxIters=1000,
> cg2dTargetResidual=1.E-13,
> &
>
> # Time stepping parameters
> &PARM03
> nIter0=0,
> nTimeSteps=21600,
> deltaT=20,
> deltaTtracer=20,
> cAdjFreq=0.,
> abEps=0.02,
> pChkptFreq=432000,
> chkptFreq=0.0,
> #dumpFreq=7200.0,
> dumpFreq=43200,
> #taveFreq=86400.0,
> monitorFreq=36000.,
> # periodicExternalForcing=.TRUE.,
> externForcingPeriod=2592000,
> externForcingCycle=31104000,
> pickupStrictlyMatch=.FALSE.,
> &
>
> # Gridding parameters
> &PARM04
> #constant delZ= 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140., 140.,
> #variable
>
> usingSphericalPolarGrid=.TRUE.,
> delX=174*0.0625,
> delY=226*0.0625,
> delZ=10*3.,10*7.,10*25.,5*100.,5*180.,
> ygOrigin=27.03125,
> xgOrigin=117.46875,
> &
>
> # Input datasets
> &PARM05
> bathyFile='topognew1.bin',
> dragQFile='dragQFile.bin',
> uVelInitFile='UVEL200201.bin',
> vVelInitFile='VVEL200201.bin',
> &
>
> # Open-boundaries
> &OBCS_PARM01
> OB_Ieast=226*-1,
> OB_Jsouth=174*1,
> useOBCSprescribe=.TRUE.,
> OBEuFile = 'ueast4.bin',
> OBSuFile = 'usouth4.bin',
> OBEvFile = 'veast4.bin',
> OBSvFile = 'vsouth4.bin',
>
> &
>
>
> Chunyan Zhou
> Division of Civil Engineering
> School of Engineering, Physics and Mathematics
> College of Art, Science and Engineering
> Fulton Building,G19
> University of Dundee
> Dundee, UK DD1 4HN
> Tel. 01382 385431
>
>
> The University of Dundee is a registered Scottish Charity, No: SC015096
> <average current run11-9 better iter=21600.jpg><nonlinfreesurf.jpg>_______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support
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