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C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_fluxlimit_adv_x.F,v 1.4 2002/03/06 01:29:36 jmc Exp $ |
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C $Name: $ |
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|
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#include "GAD_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: GAD_FLUXLIMIT_ADV_X |
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|
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C !INTERFACE: ========================================================== |
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SUBROUTINE GAD_FLUXLIMIT_ADV_X( |
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I bi,bj,k,deltaT, |
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I uTrans, uVel, |
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I maskLocW, tracer, |
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O uT, |
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I myThid ) |
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|
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C !DESCRIPTION: |
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C Calculates the area integrated zonal flux due to advection of a tracer |
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C using second-order interpolation with a flux limiter: |
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C \begin{equation*} |
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C F^x_{adv} = U \overline{ \theta }^i |
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C - \frac{1}{2} \left( |
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C [ 1 - \psi(C_r) ] |U| |
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C + U \frac{u \Delta t}{\Delta x_c} \psi(C_r) |
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C \right) \delta_i \theta |
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C \end{equation*} |
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C where the $\psi(C_r)$ is the limiter function and $C_r$ is |
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C the slope ratio. |
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|
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C !USES: =============================================================== |
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IMPLICIT NONE |
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#include "SIZE.h" |
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#include "GRID.h" |
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|
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C !INPUT PARAMETERS: =================================================== |
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C bi,bj :: tile indices |
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C k :: vertical level |
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C uTrans :: zonal volume transport |
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C uVel :: zonal flow |
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C tracer :: tracer field |
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C myThid :: thread number |
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INTEGER bi,bj,k |
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_RL deltaT |
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_RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL uVel (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy) |
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_RS maskLocW(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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INTEGER myThid |
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|
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C !OUTPUT PARAMETERS: ================================================== |
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C uT :: zonal advective flux |
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_RL uT (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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|
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C !LOCAL VARIABLES: ==================================================== |
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C i,j :: loop indices |
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C Cr :: slope ratio |
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C Rjm,Rj,Rjp :: differences at i-1,i,i+1 |
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C uFld :: velocity [m/s], zonal component |
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INTEGER i,j |
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_RL Cr,Rjm,Rj,Rjp |
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_RL uFld |
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C Statement function provides Limiter(Cr) |
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#include "GAD_FLUX_LIMITER.h" |
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CEOP |
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|
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DO j=1-Oly,sNy+Oly |
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uT(1-Olx,j)=0. |
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uT(2-Olx,j)=0. |
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uT(sNx+Olx,j)=0. |
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DO i=1-Olx+2,sNx+Olx-1 |
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|
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c uFld = uVel(i,j,k,bi,bj) |
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uFld = uTrans(i,j)*recip_dyG(i,j,bi,bj) |
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& *recip_drF(k)*recip_hFacW(i,j,k,bi,bj) |
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Rjp=(tracer(i+1,j)-tracer( i ,j))*maskLocW(i+1,j) |
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Rj =(tracer( i ,j)-tracer(i-1,j))*maskLocW( i ,j) |
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Rjm=(tracer(i-1,j)-tracer(i-2,j))*maskLocW(i-1,j) |
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|
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IF (Rj.NE.0.) THEN |
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IF (uTrans(i,j).GT.0) THEN |
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Cr=Rjm/Rj |
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ELSE |
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Cr=Rjp/Rj |
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ENDIF |
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ELSE |
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IF (uTrans(i,j).GT.0) THEN |
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Cr=Rjm*1.E20 |
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ELSE |
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Cr=Rjp*1.E20 |
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ENDIF |
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ENDIF |
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Cr=Limiter(Cr) |
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uT(i,j) = |
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& uTrans(i,j)*(Tracer(i,j)+Tracer(i-1,j))*0.5 _d 0 |
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& -0.5*( |
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& (1-Cr)*ABS(uTrans(i,j)) |
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& +uTrans(i,j)*uFld*deltaT |
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& *recip_dxC(i,j,bi,bj)*Cr |
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& )*Rj |
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ENDDO |
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ENDDO |
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|
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RETURN |
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END |
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