/[MITgcm]/MITgcm/pkg/generic_advdiff/gad_dst3fl_adv_x.F
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Revision 1.12 - (hide annotations) (download)
Tue Dec 5 22:21:50 2006 UTC (17 years, 5 months ago) by jmc
Branch: MAIN
CVS Tags: checkpoint58t_post, checkpoint58w_post, mitgcm_mapl_00, checkpoint58v_post, checkpoint58x_post, checkpoint58u_post, checkpoint58s_post
Changes since 1.11: +12 -13 lines
change horizontal CFL for deep-model.

1 jmc 1.12 C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_dst3fl_adv_x.F,v 1.11 2006/06/19 14:40:43 jmc Exp $
2 jmc 1.5 C $Name: $
3 adcroft 1.1
4     #include "GAD_OPTIONS.h"
5    
6 jmc 1.10 SUBROUTINE GAD_DST3FL_ADV_X(
7 heimbach 1.7 I bi,bj,k,deltaTloc,
8 jmc 1.10 I uTrans, uFld,
9 jmc 1.6 I maskLocW, tracer,
10 adcroft 1.1 O uT,
11     I myThid )
12     C /==========================================================\
13     C | SUBROUTINE GAD_DST3FL_ADV_X |
14     C | o Compute Zonal advective Flux of Tracer using |
15     C | 3rd Order DST Sceheme with flux limiting |
16     C |==========================================================|
17     IMPLICIT NONE
18    
19     C == GLobal variables ==
20     #include "SIZE.h"
21     #include "GRID.h"
22     #include "GAD.h"
23    
24     C == Routine arguments ==
25     INTEGER bi,bj,k
26 heimbach 1.7 _RL deltaTloc
27 adcroft 1.1 _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
28 jmc 1.10 _RL uFld (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
29 jmc 1.6 _RS maskLocW(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
30 adcroft 1.1 _RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
31     _RL uT (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
32     INTEGER myThid
33    
34     C == Local variables ==
35 jmc 1.10 C uLoc :: velocity [m/s], zonal component
36 adcroft 1.1 INTEGER i,j
37 jmc 1.12 _RL Rjm,Rj,Rjp,uCFL,d0,d1,psiP,psiM,thetaP,thetaM
38 jmc 1.10 _RL uLoc
39 jmc 1.8 _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 adcroft 1.1
46     DO j=1-Oly,sNy+Oly
47 jmc 1.8 uT(1-Olx,j)=0. _d 0
48     uT(2-Olx,j)=0. _d 0
49     uT(sNx+Olx,j)=0. _d 0
50 adcroft 1.1 DO i=1-Olx+2,sNx+Olx-1
51 jmc 1.6 Rjp=(tracer(i+1,j)-tracer( i ,j))*maskLocW(i+1,j)
52     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)
54 adcroft 1.1
55 jmc 1.11 uLoc = uFld(i,j)
56 jmc 1.12 uCFL = ABS( uLoc*deltaTloc
57     & *recip_dxC(i,j,bi,bj)*recip_deepFacC(k) )
58     d0=(2. _d 0 -uCFL)*(1. _d 0 -uCFL)*oneSixth
59     d1=(1. _d 0 -uCFL*uCFL)*oneSixth
60 jmc 1.8
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 heimbach 1.4 c thetaP=0.D0
67 jmc 1.8 c thetaM=0.D0
68 heimbach 1.4 c IF (Rj.NE.0.D0) thetaP=Rjm/Rj
69 jmc 1.8 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 adcroft 1.1 psiP=d0+d1*thetaP
83 jmc 1.12 psiP=MAX(0. _d 0,MIN(MIN(1. _d 0,psiP),
84     & thetaP*(1. _d 0 -uCFL)/(uCFL+1. _d -20) ))
85 adcroft 1.1 psiM=d0+d1*thetaM
86 jmc 1.12 psiM=MAX(0. _d 0,MIN(MIN(1. _d 0,psiM),
87     & thetaM*(1. _d 0 -uCFL)/(uCFL+1. _d -20) ))
88 jmc 1.8
89 adcroft 1.1 uT(i,j)=
90 jmc 1.12 & 0.5*(uTrans(i,j)+ABS(uTrans(i,j)))
91 heimbach 1.2 & *( Tracer(i-1,j) + psiP*Rj )
92 jmc 1.12 & +0.5*(uTrans(i,j)-ABS(uTrans(i,j)))
93 heimbach 1.2 & *( Tracer( i ,j) - psiM*Rj )
94 adcroft 1.1
95     ENDDO
96     ENDDO
97    
98     RETURN
99     END

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