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

[fancer fancer]

Jody,

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:
diffKhT=1.E-2,
diffKzT=1.E-3,
diffK4T=0.E-3,
diffShT=0.E-2,
diffSzT=0.E-3,
diffS4T=0.E-3,
momViscosity=.TRUE.,
viscAh=1.E-2,
viscAz=1.E-3,
But noise above bottom steps still present.
Is it right value?
Is there something else, what can help to restrain noises?

Sincerely,
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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