[MITgcm-support] How to reduce a reflection wave from OBCs!

[Dmitri Leonov]

Hello Van Thinh,

I've used sponge boundary conditions for a similar problem. My data.obcs 
file looks like this

 &OBCS_PARM01
 OB_Iwest=1,
 OB_Ieast=-1,
 useOBCSsponge=.TRUE.,
 &

 &OBCS_PARM03
 spongeThickness=10,
# inverse relax. coef's (seconds)
 Urelaxobcsinner = 0.0,
 Urelaxobcsbound = 32.0,
 Vrelaxobcsinner = 0.0,
 Vrelaxobcsbound = 32.0,
 &

You may want to try it.

Dmitri


Van Thinh Nguyen wrote:

> Dear all,
>
> I would like to simulate internal waves generated by tidal forcing 
> over a depression bump in a open channel (opened at east & west). My 
> case is similar to exp4, but it's limited in 2D. The tidal current is 
> from the East to West with u=Uo*sin(omega*t). At west and east OBCs I 
> set:
>
> OBWu=Uo*sin(omega*t)
> OBWv=0.
> OBWt=tRef
> OBWs=sRef
>
> OBWw=0. for nonhydrostatic
> OBWeta=Eta=0.
>
> At Eastern OBC is set the same above.
>
> I extended the length of domain from 60km, 120km, ...
> the depth of domain H=80m (shallow), depth of bump=50%*H.
>
> I got refection waves from both OBCs, because Temperature profile 
> (linearized in depth) is fixed at these OBCs (always =tRef), however 
> the temperature profile in inner domain has changed.
>
> Anyone may have an idea to help me to fix this problem?
>
> Thanks so much for your helps,
>
> Van Thinh
>
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