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

[Jody Klymak]

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 
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--
Jody Klymak
http://web.uvic.ca/~jklymak/