[MITgcm-support] problem with boundary condition on the bottom

[camili at noos.fr]

Hello,

I have a problem to understand how the 'no slip bottom' 
boundary condition is supposed to be respected.
I have runed  the exp0 presented in your tutorial. When I 
specify the boundary condition on the bottom, it seems to be 
no difference when I specify a free slip or a no slip 
condition. The velocities are the almost the same in the two 
cases.
I also runed a simulation quite similar with the exp0, but I 
put 5 layer instead of 1.
Here is the data file I used:
# Model parameters
# Continuous equation parameters
 &PARM01
 tRef=20.,20.,20.,20.,20.,
 sRef=10.,10.,10.,10.,10.,
 viscAz=1.E-2,
 viscAh=4.E2,
 diffKhT=4.E2,
 diffKzT=1.E-2,
 no_slip_sides=.FALSE.,
 no_slip_bottom=.FALSE.,
 beta=1.E-11,
 tAlpha=2.E-4,
 sBeta =0.,
 gravity=9.81,
 gBaro=9.81,
 rigidLid=.FALSE.,
 implicitFreeSurface=.TRUE.,
 eosType='LINEAR',
 readBinaryPrec=64,
 &
# Elliptic solver parameters
 &PARM02
 cg2dMaxIters=1000,
 cg2dTargetResidual=1.E-7,
 &
 # Time stepping parameters
 &PARM03
 startTime=0,
 endTime=15552000.0,
 deltaTmom=500.0,
 deltaTtracer=500.0,
 abEps=0.1,
 pChkptFreq=604800.0,
 chkptFreq=604800.0,
 dumpFreq=604800.0,
 monitorFreq=604800.,
 &
# Gridding parameters
 &PARM04
 usingCartesianGrid=.FALSE.,
 usingSphericalPolarGrid=.TRUE.,
 delX=100*0.2,
 delY=100*0.2,
 delZ=1000.,1000.,1000.,1000.,1000.,
 phiMin=35.,
 &
 &PARM05
 bathyFile='topog.box',
 hydrogThetaFile=,
 hydrogSaltFile=,
 zonalWindFile='windx.sin_y',
 meridWindFile=,

And once again the velocities are not null on the bottom. And 
when I run the same simulation with a free slip condition on 
the bottom, the differences between the velocities of the 2 
experiments are really weak.

So could you help me to understand how the boundary condition 
on the bottom is supposed to influence the velocity field, 
specialy in the under layer?

Thanks a lot,
Camille


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