[MITgcm-support] Smagorinsky viscosity

[Jody Klymak]

Hi Malte,

I just looked into this with Ruth Musgrave's help as well.  3-D Smagorinsky works pretty well. Your grid can be anisotropic, but probably not too anisotropic.  If you are using non-hydrostatic you probably don't want a grid that is too anisotropic anyways.   As written, it does not do any enhanced diffusivity, though I have a straight forward mod to enhance the diffusivities as well.  I guess I dont' know about any issues with the vertical advection scheme.  I'd have to take a look at it.  

I believe it just uses Dearborn's scheme.  So the Smagorinsky constant is just a constant.  I found to get energy to balance you had to tune this constant, so it would be great if someone moved towards a Germano type scheme.

I dont' have access to my files right now, but will in a few hours, but its pretty straightforward to try.  A little less straightforward if you want your own diagnostics into the dissipation terms and matching diffusivity.

I don't know anything about 2-D Smagorinsky.  

Cheers,   Jody

> On Mar 12, 2015, at  4:03 AM, Malte Jansen <mfj at uchicago.edu> wrote:
> 
> Hi all,
> 
> Can anybody give me (or point me to) a brief update on the Smagorinsky viscosity implementation? The documentation seems to say that the vertical component of the Smagorinsky viscosity has not yet been implemented. Is that still true? 
> 
> I also found an old post stating that Smag does not yet work at all for the non-hydrostatic version. Is that still true?
> 
> There now also is a Smag3D. Is there any documentation for that? Do I see it correctly that Smag3D is fully isotropic (and thus probably not recommended if the model grid is anisotropic)?
> 
> I am running a non-hydrostatic model with non-isotropic grid. So my question is basically if there is an existing implementation of the Smagorinsky viscosity that should be adequate?
> 
> Thanks,
> Malte
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support