[MITgcm-support] Internal waves. Noise near bottom.

fancer fancer fancer.lancer at gmail.com
Sun May 1 02:37:10 EDT 2011


Thanks for response.
Now I've put diffusion, but still with no positive results (pictures with
U,W and T in attach). I've set:
But noise above bottom steps still present.
Is it right value?
Is there something else, what can help to restrain noises?

Serge Semin

On Fri, Apr 29, 2011 at 10:12 PM, Jody Klymak <jklymak at uvic.ca> wrote:

> Serge,
> According to your "data" file you have no explicit viscosity or diffusion.
> So any internal waves generated at the steps rattle around with only
> numerical diffusivity to dissipate them.  I'd put some diffusivity and
> viscosity in, even if it is molecular.
> Cheers,  Jody
> On Apr 28, 2011, at  12:23 PM, fancer fancer wrote:
>  Hi Dear Modelers,
>> I am trying to model ideal case of internal waves propagation in closed
>> basin without free surface (rigid lid) in 2D area with two layer
>> stratification (linear tilting) and parabolic bottom.
>> Now I faced with problem of partial discretization. I can not get a
>> simulation without noises near the largest steps of the bottom.
>> I've tried to set various dx, dz and dt steps, but without positive
>> result. I've tried to use  various tempAdvScheme (33, 77), unfortunately
>> with same result. And finally I've tried to set various hFacMin, now it is
>> in 0.00005 value (best results), but it didn't helped me too.
>> We have an results of modelling through other system with sigma-coordinate
>> discretization, where we set 1000x50 points on 10000x10 m grid. There's no
>> noise.
>> I put the pictures with T, U and W of modeling in result directory of
>> attached project.
>> Could you tell me how should I modify my project (in attach) for clearing
>> the model? or how should I calculate dx and dz steps for model
>> stabilization? (CFL in norm)
>> And one more question. My area is 2D (z and x coordinates), but models
>> stability depends of dy step. Is this normal or something wrong with my
>> project? If second is true, could you tell me that can be wrong?
>> Thanks for help in advance.
>> Sincerely,
>> Serge Semin
>> <01_tilting_stratification_parabola.tar.gz>_______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mitgcm.org/mailman/listinfo/mitgcm-support
> --
> Jody Klymak
> http://web.uvic.ca/~jklymak/
> _______________________________________________
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> MITgcm-support at mitgcm.org
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