[MITgcm-support] LES and SMAG_3D?

Jody Klymak jklymak at uvic.ca
Fri Nov 21 23:06:33 EST 2014


Thanks Dustin,

Yes, reading the code, its definitely a constant-co-efficient implementation.  I also don't see that it applies a similar sub-gridscale closure to the tracer fields.  

A fun question is if it is worth doing all the above, or applying a Deardorff '80-type scheme where TKE is prognostically tracked.  However, the strain tensor is calculated *and stored* so applying the scale filters for the Germano scheme shouldn't be too hard.  

> viscAh=2.E-3,
> viscAz=2.E-3,
> smag3D_coeff = 0.01,

Hmmm, that's *almost* DNS depending on your Reynolds number.  And that co-efficient is pretty small, isn't it?  I thought the default Smagorinski was more like 0.1?  But maybe MITgcm normalizes differently.  I find the code a bit opaque (what is twoRL - grep doesn't help me know where it is defined)..  

Thanks,   Jody


> for 1-m resolution
> 
> Also, there is an example under
> verification/tutorial_deep_convection/input.smag3d/
> 
> I’m sure Jean-Michel will have more to say about it, I’ll let you know how my results turn out.
> 
> Cheers,
> Dustin
> 
>> On Nov 21, 2014, at 3:16 PM, Jody Klymak <jklymak at uvic.ca> wrote:
>> 
>> 
>> Hi All,
>> 
>> Before I hurt my head too much, is there a reference or documentation for the smag3D code that is in pkg/mom_common?  Does this feature work?  And does it support dynamic (Germano 91) co-efficients?
>> 
>> I want to do some isotropic LES-scale modelling, and maybe this is a way to make it happen.
>> 
>> Thanks,   Jody
>> 
>> 
>> --
>> Jody Klymak    
>> http://web.uvic.ca/~jklymak/
>> 
>> 
>> 
>> 
>> 
>> 
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--
Jody Klymak    
http://web.uvic.ca/~jklymak/








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