/[MITgcm]/MITgcm/pkg/generic_advdiff/gad_dst3fl_adv_x.F
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revision 1.7 by heimbach, Fri Aug 19 22:19:35 2005 UTC revision 1.12 by jmc, Tue Dec 5 22:21:50 2006 UTC
# Line 3  C $Name$ Line 3  C $Name$
3    
4  #include "GAD_OPTIONS.h"  #include "GAD_OPTIONS.h"
5    
6        SUBROUTINE GAD_DST3FL_ADV_X(        SUBROUTINE GAD_DST3FL_ADV_X(
7       I           bi,bj,k,deltaTloc,       I           bi,bj,k,deltaTloc,
8       I           uTrans, uVel,       I           uTrans, uFld,
9       I           maskLocW, tracer,       I           maskLocW, tracer,
10       O           uT,       O           uT,
11       I           myThid )       I           myThid )
# Line 25  C     == Routine arguments == Line 25  C     == Routine arguments ==
25        INTEGER bi,bj,k        INTEGER bi,bj,k
26        _RL deltaTloc        _RL deltaTloc
27        _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)        _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
28        _RL uVel(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)        _RL uFld  (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
29        _RS maskLocW(1-OLx:sNx+OLx,1-OLy:sNy+OLy)        _RS maskLocW(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
30        _RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)        _RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
31        _RL uT    (1-OLx:sNx+OLx,1-OLy:sNy+OLy)        _RL uT    (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
32        INTEGER myThid        INTEGER myThid
33    
34  C     == Local variables ==  C     == Local variables ==
35  C     uFld   :: velocity [m/s], zonal component  C     uLoc   :: velocity [m/s], zonal component
36        INTEGER i,j        INTEGER i,j
37        _RL Rjm,Rj,Rjp,cfl,d0,d1,psiP,psiM,thetaP,thetaM        _RL Rjm,Rj,Rjp,uCFL,d0,d1,psiP,psiM,thetaP,thetaM
38        _RL uFld        _RL uLoc
39          _RL thetaMax
40          PARAMETER( thetaMax = 1.D+20 )
41    
42    C- jmc: an alternative would be to compute directly psiM*Rj & psiP*Rj
43    C       (if Rj*Rjm < 0 => psiP*Rj = 0 , elsef Rj > 0 ... , else  ... )
44    C       with no need to compute thetaM (might be easier to differentiate)
45    
46        DO j=1-Oly,sNy+Oly        DO j=1-Oly,sNy+Oly
47         uT(1-Olx,j)=0.D0         uT(1-Olx,j)=0. _d 0
48         uT(2-Olx,j)=0.D0         uT(2-Olx,j)=0. _d 0
49         uT(sNx+Olx,j)=0.D0         uT(sNx+Olx,j)=0. _d 0
50         DO i=1-Olx+2,sNx+Olx-1         DO i=1-Olx+2,sNx+Olx-1
51          Rjp=(tracer(i+1,j)-tracer( i ,j))*maskLocW(i+1,j)          Rjp=(tracer(i+1,j)-tracer( i ,j))*maskLocW(i+1,j)
52          Rj =(tracer( i ,j)-tracer(i-1,j))*maskLocW( i ,j)          Rj =(tracer( i ,j)-tracer(i-1,j))*maskLocW( i ,j)
53          Rjm=(tracer(i-1,j)-tracer(i-2,j))*maskLocW(i-1,j)          Rjm=(tracer(i-1,j)-tracer(i-2,j))*maskLocW(i-1,j)
54    
55  c       uFld = uVel(i,j,k,bi,bj)          uLoc = uFld(i,j)
56          uFld = uTrans(i,j)*recip_dyG(i,j,bi,bj)          uCFL = ABS( uLoc*deltaTloc
57       &       *recip_drF(k)*recip_hFacW(i,j,k,bi,bj)       &                  *recip_dxC(i,j,bi,bj)*recip_deepFacC(k) )
58          cfl=abs(uFld*deltaTloc*recip_dxC(i,j,bi,bj))          d0=(2. _d 0 -uCFL)*(1. _d 0 -uCFL)*oneSixth
59          d0=(2.D0-cfl)*(1.D0-cfl)*oneSixth          d1=(1. _d 0 -uCFL*uCFL)*oneSixth
60          d1=(1.D0-cfl*cfl)*oneSixth  
61    C-      the old version: can produce overflow, division by zero,
62    c       and is wrong for tracer with low concentration:
63    c       thetaP=Rjm/(1.D-20+Rj)
64    c       thetaM=Rjp/(1.D-20+Rj)
65    C-      the right expression, but not bounded:
66  c       thetaP=0.D0  c       thetaP=0.D0
 c       IF (Rj.NE.0.D0) thetaP=Rjm/Rj  
         thetaP=Rjm/(1.D-20+Rj)  
         psiP=d0+d1*thetaP  
         psiP=max(0.D0, min(min(1.D0,psiP),  
      &       (1.D0-cfl)/(1.D-20+cfl)*thetaP))  
         thetaM=Rjp/(1.D-20+Rj)  
67  c       thetaM=0.D0  c       thetaM=0.D0
68    c       IF (Rj.NE.0.D0) thetaP=Rjm/Rj
69  c       IF (Rj.NE.0.D0) thetaM=Rjp/Rj  c       IF (Rj.NE.0.D0) thetaM=Rjp/Rj
70    C-      prevent |thetaP,M| to reach too big value:
71            IF ( ABS(Rj)*thetaMax .LE. ABS(Rjm) ) THEN
72              thetaP=SIGN(thetaMax,Rjm*Rj)
73            ELSE
74              thetaP=Rjm/Rj
75            ENDIF
76            IF ( ABS(Rj)*thetaMax .LE. ABS(Rjp) ) THEN
77              thetaM=SIGN(thetaMax,Rjp*Rj)
78            ELSE
79              thetaM=Rjp/Rj
80            ENDIF
81    
82            psiP=d0+d1*thetaP
83            psiP=MAX(0. _d 0,MIN(MIN(1. _d 0,psiP),
84         &                       thetaP*(1. _d 0 -uCFL)/(uCFL+1. _d -20) ))
85          psiM=d0+d1*thetaM          psiM=d0+d1*thetaM
86          psiM=max(0.D0, min(min(1.D0,psiM),          psiM=MAX(0. _d 0,MIN(MIN(1. _d 0,psiM),
87       &       (1.D0-cfl)/(1.D-20+cfl)*thetaM))       &                       thetaM*(1. _d 0 -uCFL)/(uCFL+1. _d -20) ))
88    
89          uT(i,j)=          uT(i,j)=
90       &   0.5*(uTrans(i,j)+abs(uTrans(i,j)))       &   0.5*(uTrans(i,j)+ABS(uTrans(i,j)))
91       &      *( Tracer(i-1,j) + psiP*Rj )       &      *( Tracer(i-1,j) + psiP*Rj )
92       &  +0.5*(uTrans(i,j)-abs(uTrans(i,j)))       &  +0.5*(uTrans(i,j)-ABS(uTrans(i,j)))
93       &      *( Tracer( i ,j) - psiM*Rj )       &      *( Tracer( i ,j) - psiM*Rj )
94    
95         ENDDO         ENDDO
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