[Mitgcm-support] Re: free slip/no slip

[mitgcm-support at dev.mitgcm.org]

Hi Alistair,

thank for the fast answer. We will make another test with free/no slip
on Monday. 

Another question: Is the shaved cell option still in the mitgcmuv code?

Arne

Alistair Adcroft wrote:
> 
> Hi Arne,
> 
> C     Eddy component of vertical flux
>       IF (no_slip_bottom) THEN
>        DO j=jMin,jMax
>         DO i=iMin,iMax
>          vf(i,j) =
>      &   -KappaRU(i,j,k)
>      & *_RA_AT_W
>      &   *( ( 2.-_maskW(i,j,k,bi,bj) )*uVel(i,j,kM1,bi,bj)
>      &     -     _maskW(i,j,k,bi,bj)  *uVel(i,j,k,bi,bj)
>      &    )*rkFac*recip_drC(k)
>         ENDDO
>        ENDDO
>       ELSE
>        DO j=jMin,jMax
>         DO i=iMin,iMax
>          vf(i,j) =
>      &   -KappaRU(i,j,k)
>      & *_RA_AT_W
>      &   *( uVel(i,j,km1,bi,bj)-uVel(i,j,k,bi,bj)
>      &    )*rkFac*recip_drC(k)
>      &    *_maskW(i,j,k,bi,bj)*rVelMaskOverride
>         ENDDO
>        ENDDO
>       ENDIF
> 
> no_slip_bottom=.TRUE., in interior maskW(k)=1
> so  ( 2-maskW(k) ) U(k-1) - maskW(k) U(k)
>     =  1 U(k-1) - 1 U(k)
> 
> no_slip_bottom=.TRUE., at bottom maskW(k)=0
> so  ( 2-maskW(k) ) U(k-1) - maskW(k) U(k)
>     =  2 U(k-1) - 0 U(k)
> 
> no_slip_bottom=.FALSE., in interior maskW(k)=1
> so  maskW(k) [ U(k-1) - maskW(k) U(k) ]
>     =  1 [ U(k-1) - 1 U(k) ]
> 
> no_slip_bottom=.FALSE., at bottom maskW(k)=0
> so  maskW(k) [ U(k-1) - maskW(k) U(k) ]
>     =  0 [ U(k-1) - 1 U(k) ]
> 
> Looks right to me. This is the sort of code
> that doesn't get tested properly (beyond me thinking
> about it) so if you're convinced it's wrong
> show me a test.
> 
> Regards,
> 
> Alistair.
> PS> I would dearly love to tidy up calc_mom_rhs(). It
> takes much more CPU than it should mostly because
> of using these intermediate arrays like vf, af and df.
> One day ...

-- 

Dr. Arne Biastoch
Scripps Institution of Oceanography        phone: +1-858-822-3787
Physical Oceanography Research Division    fax  : +1-858-534-9820
MS: 0230                                   email: abiastoch at ucsd.edu
8605 La Jolla Shores Dr.            
La Jolla, CA 92093-0230, U.S.A.   http://www.ecco.ucsd.edu/~biastoch