[MITgcm-support] Minimum Viscosities

[Christopher L. Wolfe]

Ryan,

If you have zonal boundaries, you need to set viscAh large enough to  
resolve the Munk boundary layer ~(Ah/beta)^(1/3). I like to have 2-3  
grid points in the Munk layer. If you don't resolve the Munk layer  
you can get grid modes in the barotropic streamfunction.

If you use implicit vertical viscosity, I think you can make the  
vertical viscosity as small as you want it. You might even be able to  
set it to zero at let numerical viscosity do all the work for you.  
I'm sure someone will correct me on this if I'm wrong.

Cheers,
Christopher

-----------------------------------------------------------
Dr. Christopher L. Wolfe                   858-534-4560
Physical Oceanography Research Division    OAR 357
Scripps Institution of Oceanography, UCSD  clwolfe at ucsd.edu
-----------------------------------------------------------




On Jul 1, 2009, at 2:23 PM, Ryan Abernathey wrote:

> Hello MITgcm People,
>
> Is there a general rule for determining what the *minimum* possible
> horizontal and vertical viscosities (viscAh & viscAr) should be for a
> given configuration?
>
> Or do you just have to experiment until you find settings that are
> stable?
>
> Thanks again,
> __________________
> Ryan Abernathey
> rpa at mit.edu
> MIT Ph.D. Student
> Program in Oceans Atmospheres & Climate
> http://web.mit.edu/rpa/
>
>
>
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