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C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_dst3fl_adv_y.F,v 1.12 2006/12/05 22:21:50 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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SUBROUTINE GAD_DST3FL_ADV_Y( |
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I bi,bj,k, calcCFL, deltaTloc, |
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I vTrans, vFld, |
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I maskLocS, tracer, |
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O vT, |
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I myThid ) |
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C /==========================================================\ |
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C | SUBROUTINE GAD_DST3FL_ADV_Y | |
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C | o Compute Meridional advective Flux of Tracer using | |
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C | 3rd Order DST Sceheme with flux limiting | |
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C |==========================================================| |
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IMPLICIT NONE |
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|
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C == GLobal variables == |
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#include "SIZE.h" |
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#include "GRID.h" |
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#include "GAD.h" |
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|
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C == Routine arguments == |
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INTEGER bi,bj,k |
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LOGICAL calcCFL |
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_RL deltaTloc |
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_RL vTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL vFld (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RS maskLocS(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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_RL vT (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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INTEGER myThid |
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|
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C == Local variables == |
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INTEGER i,j |
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_RL Rjm,Rj,Rjp,vCFL,d0,d1,psiP,psiM,thetaP,thetaM |
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_RL thetaMax |
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PARAMETER( thetaMax = 1.D+20 ) |
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|
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DO i=1-Olx,sNx+Olx |
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vT(i,1-Oly)=0. _d 0 |
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vT(i,2-Oly)=0. _d 0 |
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vT(i,sNy+Oly)=0. _d 0 |
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ENDDO |
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DO j=1-Oly+2,sNy+Oly-1 |
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DO i=1-Olx,sNx+Olx |
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Rjp=(tracer(i,j+1)-tracer(i, j ))*maskLocS(i,j+1) |
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Rj =(tracer(i, j )-tracer(i,j-1))*maskLocS(i, j ) |
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Rjm=(tracer(i,j-1)-tracer(i,j-2))*maskLocS(i,j-1) |
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|
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vCFL = vFld(i,j) |
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IF ( calcCFL ) vCFL = ABS( vFld(i,j)*deltaTloc |
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& *recip_dyC(i,j,bi,bj)*recip_deepFacC(k) ) |
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d0=(2. _d 0 -vCFL)*(1. _d 0 -vCFL)*oneSixth |
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d1=(1. _d 0 -vCFL*vCFL)*oneSixth |
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|
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C- the old version: can produce overflow, division by zero, |
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c and is wrong for tracer with low concentration: |
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c thetaP=Rjm/(1.D-20+Rj) |
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c thetaM=Rjp/(1.D-20+Rj) |
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C- the right expression, but not bounded: |
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c thetaP=0.D0 |
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c thetaM=0.D0 |
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c IF (Rj.NE.0.D0) thetaP=Rjm/Rj |
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c IF (Rj.NE.0.D0) thetaM=Rjp/Rj |
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C- prevent |thetaP,M| to reach too big value: |
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IF ( ABS(Rj)*thetaMax .LE. ABS(Rjm) ) THEN |
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thetaP=SIGN(thetaMax,Rjm*Rj) |
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ELSE |
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thetaP=Rjm/Rj |
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ENDIF |
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IF ( ABS(Rj)*thetaMax .LE. ABS(Rjp) ) THEN |
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thetaM=SIGN(thetaMax,Rjp*Rj) |
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ELSE |
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thetaM=Rjp/Rj |
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ENDIF |
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|
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psiP=d0+d1*thetaP |
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psiP=MAX(0. _d 0,MIN(MIN(1. _d 0,psiP), |
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& thetaP*(1. _d 0 -vCFL)/(vCFL+1. _d -20) )) |
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psiM=d0+d1*thetaM |
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psiM=MAX(0. _d 0,MIN(MIN(1. _d 0,psiM), |
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& thetaM*(1. _d 0 -vCFL)/(vCFL+1. _d -20) )) |
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|
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vT(i,j)= |
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& 0.5*(vTrans(i,j)+ABS(vTrans(i,j))) |
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& *( Tracer(i,j-1) + psiP*Rj ) |
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& +0.5*(vTrans(i,j)-ABS(vTrans(i,j))) |
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& *( Tracer(i, j ) - psiM*Rj ) |
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|
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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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