[MITgcm-support] viscAh & viscAz!

[Van Thinh Nguyen]

Dear MITgcm-supporters & users,

I am using MITgcm to simulate internal waves in a tilting tank ( a
closed rectangular tank (4000x10x40) m with a slope of pycnocline, it may
consider as a 2 two layers model with temperatures of upper/lower are 18/10 C degree,
without wind force!).

When I used:
viscAh=1.E-4 and viscAz=1.E-4 (with diffKhT=2.E-6 and diffKzT=1.E-7).
It worked ok.

But when I changed to viscAh=2.E-6 and viscAz=2.E-6, I got an extreme
noise. I even reduced to very small time steps and changed the model to
4/5 layers in depth (Temp.=18/16/14/12/10).

If anyone would know how can I improve this noise, please give an advice.

Thanks so much for your helps. I attached herewith my data file!

Van Thinh


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# Model parameters
# Continuous equation parameters
 &PARM01
 tRef=,  
 sRef=81*10., 
 viscAz=2.E-6,
# implicitViscosity=.TRUE.,
 viscAh=2.E-6,
 no_slip_sides=.FALSE.,
 no_slip_bottom=.FALSE., 
 diffKhT=2.E-6,
 diffKzT=1.E-7,
 f0=1E-4, 
# beta=1.E-11,
 beta=0.
 tAlpha=2.E-4,
 sBeta =0.,
 gravity=9.81,
 rigidLid=.FALSE.,
 implicitFreeSurface=.TRUE.,
 nonHydrostatic=.TRUE., 
 eosType='LINEAR',
 readBinaryPrec=64,
 &
# Elliptic solver parameters
 &PARM02
 cg2dMaxIters=1000,
 cg2dTargetResidual=1.E-8,
 &
# Time stepping parameters
 &PARM03
 startTime=0.,
#endTime=311040000,
 endTime=48000.0,
 deltaTmom=0.2,
 deltaTtracer=0.2,
 abEps=0.1,
 pChkptFreq=4800.0,
 chkptFreq=4800.0,
 dumpFreq=240.0,
# dumpFreq=2592000.0,
 monitorFreq=1.,
 &
# Gridding parameters
 &PARM04
 usingCartesianGrid=.TRUE.,
 usingSphericalPolarGrid=.FALSE.,
 delX=800*5,
 delY=2*5,
 delZ=81*0.5, 
 &
 &PARM05
 bathyFile='topog.box',
 hydrogThetaFile= 'ini_temp',
 hydrogSaltFile=,
 zonalWindFile=,
 meridWindFile=,
 &