[MITgcm-support] generate a stable current field

[Jean-Michel Campin]

Hi Pu,

I just want to add one thing:
You could take a look at verification/exp4 (see README file there)
which provides a simple example of the use of pkg/obcs
(without pkg/exf, pkg/cal) with no other forcing than the OBC
at Western & Eastern boundary (+ a gausian bump in the middle of 
the channel). It's often easier to start from a working set-up
and to make it evolves step by step rather than starting from nothing.
However, note that few selected parameters (e.g., nonHydrostatic=.TRUE.,
or time-varying OBC: 
# for time dependent open boundary conditions, activate the following 3 lines:
in parameter file "data") are not strickly necessary
but just there to test more features.

Cheers,
Jean-Michel

On Mon, Jul 06, 2015 at 11:37:49AM -0700, Matthew Mazloff wrote:
> Hi Pu
> 
> (1) and (2) seem correct. But you have to define the  obcs time period:
> obcsWperiod         =  86400,
> in data.exf.
> 
> Do you have the cal and exf packages enabled? I am not sure if having a time variable obcs is possible without them?
> 
> Unfortunately there is no verification experiment exactly like what you want, but these may help:
> 
> verification/obcs_ctrl
> verification/seaice_obcs
> 
> Matt
> 
> 
> On Jul 5, 2015, at 2:13 PM, <guopu at scsio.ac.cn> wrote:
> 
> > Hello Sir,
> > 
> > I feel the OBCS package is so complicate, so I start from generating a simple current field to understand this package. Now I have 3 questions:
> > 
> > 1. I build a 2D region with uniform depth 1000m, and set OB_Iwest=1, OB_Ieast=-1. Now I am wondering how to generate a stable barotropic current in this region. The only effective way I found is to use files containing uniform velocity for parameters: "uVelInitFile", "OBWuFile", and "OBEuFile". Is it right? or is there another "standard procedure" ?
> > 
> > 2. I want to generate above current field by only one prescribe file for "OBWuFile", so I make this (1*Nr*50)-dimension file with gradually increased velocity, from 0 (or 0.01) to 0.1m/s in 50 "time levels". However, the model results show that U at west boundary keep to be zero (or 0.01m/s). What could be the reason for this? and what is the meaning of "time levels"?
> > 
> > 3. I add a Gaussian shape obstacle on the bottom and hope to see what will happen in this region. Should I turn on one or some of these flags: useOBCSsponge, useOrlanskiEast/West, useOBCS_balance? I thought the "OB_Iwest=1, OB_Ieast=-1" would be enough to let water/waves flow/propagate out freely.
> > 
> > Studying this package has cost me several weeks, I am hungry for help, thanks!
> > 
> > Pu
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
> 

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