/[MITgcm]/MITgcm/pkg/generic_advdiff/gad_dst3fl_adv_x.F
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Revision 1.13 - (hide annotations) (download)
Wed Apr 4 01:39:06 2007 UTC (17 years, 1 month ago) by jmc
Branch: MAIN
CVS Tags: checkpoint59, checkpoint58y_post, checkpoint59e, checkpoint59d, checkpoint59g, checkpoint59f, checkpoint59a, checkpoint59c, checkpoint59b, checkpoint59m, checkpoint59l, checkpoint59n, checkpoint59i, checkpoint59h, checkpoint59k, checkpoint59j
Changes since 1.12: +5 -6 lines
add a logical argument "calcCFL" to DST horizontal Advection S/R
(if false, assume that uFld,vFld are already CFL number in x,y dir)

1 jmc 1.13 C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_dst3fl_adv_x.F,v 1.12 2006/12/05 22:21:50 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 jmc 1.13 I bi,bj,k, calcCFL, 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 jmc 1.13 LOGICAL calcCFL
27 heimbach 1.7 _RL deltaTloc
28 adcroft 1.1 _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
29 jmc 1.10 _RL uFld (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
30 jmc 1.6 _RS maskLocW(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
31 adcroft 1.1 _RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
32     _RL uT (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
33     INTEGER myThid
34    
35     C == Local variables ==
36     INTEGER i,j
37 jmc 1.12 _RL Rjm,Rj,Rjp,uCFL,d0,d1,psiP,psiM,thetaP,thetaM
38 jmc 1.8 _RL thetaMax
39     PARAMETER( thetaMax = 1.D+20 )
40    
41     C- jmc: an alternative would be to compute directly psiM*Rj & psiP*Rj
42     C (if Rj*Rjm < 0 => psiP*Rj = 0 , elsef Rj > 0 ... , else ... )
43     C with no need to compute thetaM (might be easier to differentiate)
44 adcroft 1.1
45     DO j=1-Oly,sNy+Oly
46 jmc 1.8 uT(1-Olx,j)=0. _d 0
47     uT(2-Olx,j)=0. _d 0
48     uT(sNx+Olx,j)=0. _d 0
49 adcroft 1.1 DO i=1-Olx+2,sNx+Olx-1
50 jmc 1.6 Rjp=(tracer(i+1,j)-tracer( i ,j))*maskLocW(i+1,j)
51     Rj =(tracer( i ,j)-tracer(i-1,j))*maskLocW( i ,j)
52     Rjm=(tracer(i-1,j)-tracer(i-2,j))*maskLocW(i-1,j)
53 adcroft 1.1
54 jmc 1.13 uCFL = uFld(i,j)
55     IF ( calcCFL ) uCFL = ABS( uFld(i,j)*deltaTloc
56 jmc 1.12 & *recip_dxC(i,j,bi,bj)*recip_deepFacC(k) )
57     d0=(2. _d 0 -uCFL)*(1. _d 0 -uCFL)*oneSixth
58     d1=(1. _d 0 -uCFL*uCFL)*oneSixth
59 jmc 1.8
60     C- the old version: can produce overflow, division by zero,
61     c and is wrong for tracer with low concentration:
62     c thetaP=Rjm/(1.D-20+Rj)
63     c thetaM=Rjp/(1.D-20+Rj)
64     C- the right expression, but not bounded:
65 heimbach 1.4 c thetaP=0.D0
66 jmc 1.8 c thetaM=0.D0
67 heimbach 1.4 c IF (Rj.NE.0.D0) thetaP=Rjm/Rj
68 jmc 1.8 c IF (Rj.NE.0.D0) thetaM=Rjp/Rj
69     C- prevent |thetaP,M| to reach too big value:
70     IF ( ABS(Rj)*thetaMax .LE. ABS(Rjm) ) THEN
71     thetaP=SIGN(thetaMax,Rjm*Rj)
72     ELSE
73     thetaP=Rjm/Rj
74     ENDIF
75     IF ( ABS(Rj)*thetaMax .LE. ABS(Rjp) ) THEN
76     thetaM=SIGN(thetaMax,Rjp*Rj)
77     ELSE
78     thetaM=Rjp/Rj
79     ENDIF
80    
81 adcroft 1.1 psiP=d0+d1*thetaP
82 jmc 1.12 psiP=MAX(0. _d 0,MIN(MIN(1. _d 0,psiP),
83     & thetaP*(1. _d 0 -uCFL)/(uCFL+1. _d -20) ))
84 adcroft 1.1 psiM=d0+d1*thetaM
85 jmc 1.12 psiM=MAX(0. _d 0,MIN(MIN(1. _d 0,psiM),
86     & thetaM*(1. _d 0 -uCFL)/(uCFL+1. _d -20) ))
87 jmc 1.8
88 adcroft 1.1 uT(i,j)=
89 jmc 1.12 & 0.5*(uTrans(i,j)+ABS(uTrans(i,j)))
90 heimbach 1.2 & *( Tracer(i-1,j) + psiP*Rj )
91 jmc 1.12 & +0.5*(uTrans(i,j)-ABS(uTrans(i,j)))
92 heimbach 1.2 & *( Tracer( i ,j) - psiM*Rj )
93 adcroft 1.1
94     ENDDO
95     ENDDO
96    
97     RETURN
98     END

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