/[MITgcm]/MITgcm/pkg/generic_advdiff/gad_dst3fl_impl_r.F
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Revision 1.1 - (hide annotations) (download)
Sat Oct 22 20:17:44 2005 UTC (18 years, 7 months ago) by jmc
Branch: MAIN
CVS Tags: checkpoint57w_post
add code to solve implicitly vertical advection using
 DST2, 1rst.O.Upwind, DST3 or DST3_Flux-Limit advection schemes

1 jmc 1.1 C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_u3c4_impl_r.F,v 1.5 2005/06/22 00:27:47 jmc Exp $
2     C $Name: $
3    
4     #include "GAD_OPTIONS.h"
5    
6     CBOP
7     C !ROUTINE: GAD_DST3FL_IMPL_R
8     C !INTERFACE:
9     SUBROUTINE GAD_DST3FL_IMPL_R(
10     I bi,bj,k, iMin,iMax,jMin,jMax,
11     I deltaTarg, rTrans, tFld,
12     O a5d, b5d, c5d, d5d, e5d,
13     I myThid )
14    
15     C !DESCRIPTION:
16    
17     C Compute matrix element to solve vertical advection implicitly
18     C using 3rd order Direct Space and Time (DST) advection scheme
19     C with Flux-Limiter.
20     C Method:
21     C contribution of vertical transport at interface k is added
22     C to matrix lines k and k-1
23    
24     C !USES:
25     IMPLICIT NONE
26    
27     C == Global variables ===
28     #include "SIZE.h"
29     #include "GRID.h"
30     #include "EEPARAMS.h"
31     #include "PARAMS.h"
32     #include "GAD.h"
33    
34     C !INPUT/OUTPUT PARAMETERS:
35     C == Routine Arguments ==
36     C bi,bj :: tile indices
37     C k :: vertical level
38     C iMin,iMax :: computation domain
39     C jMin,jMax :: computation domain
40     C deltaTarg :: time step
41     C rTrans :: vertical volume transport
42     C tFld :: tracer field
43     C a5d :: 2nd lower diag of pentadiagonal matrix
44     C b5d :: 1rst lower diag of pentadiagonal matrix
45     C c5d :: main diag of pentadiagonal matrix
46     C d5d :: 1rst upper diag of pentadiagonal matrix
47     C e5d :: 2nd upper diag of pentadiagonal matrix
48     C myThid :: thread number
49     INTEGER bi,bj,k
50     INTEGER iMin,iMax,jMin,jMax
51     _RL deltaTarg(Nr)
52     _RL rTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
53     _RL tFld (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
54     _RL a5d (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
55     _RL b5d (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
56     _RL c5d (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
57     _RL d5d (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
58     _RL e5d (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
59     INTEGER myThid
60    
61     C == Local Variables ==
62     C i,j :: loop indices
63     C kp1 :: =min( k+1 , Nr )
64     C km2 :: =max( k-2 , 1 )
65     C wCFL :: Courant-Friedrich-Levy number
66     C lowFac :: low order term factor
67     C highFac :: high order term factor
68     C rCenter :: centered contribution
69     C rUpwind :: upwind contribution
70     C rC4km, rC4kp :: high order contributions
71     LOGICAL flagC4
72     INTEGER i,j,kp1,km2
73     _RL wCFL, rCenter, rUpwind
74     _RL lowFac (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
75     _RL highFac(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
76     _RL rC4km, rC4kp
77     _RL mskM, mskP, maskM2, maskP1
78     _RL Rj, Rjh, cL1, cH3, cM2, th1, th2
79     _RL deltaTcfl
80     CEOP
81    
82     C-- process interior interface only:
83     IF ( k.GT.1 .AND. k.LE.Nr ) THEN
84    
85     km2=MAX(1,k-2)
86     kp1=MIN(Nr,k+1)
87     maskP1 = 1. _d 0
88     maskM2 = 1. _d 0
89     IF ( k.LE.2 ) maskM2 = 0. _d 0
90     IF ( k.GE.Nr) maskP1 = 0. _d 0
91    
92     C-- Compute the low-order term & high-order term fractions :
93     deltaTcfl = deltaTarg(k)
94     C DST-3 Flux-Limiter Advection Scheme:
95     C- Limiter: Psi=max(0,min(1,cL1+theta*cH1,theta*(1-cfl)/cfl) )
96     C with theta=Rjh/Rj ;
97     C is linearize arround the current value of theta(tFld) & cfl:
98     C lowFac & highFac are set such as Psi*Rj = lowFac*Rj + highFac*Rjh
99     DO j=jMin,jMax
100     DO i=iMin,iMax
101     wCFL = deltaTcfl*ABS(rTrans(i,j))
102     & *recip_rA(i,j,bi,bj)*recip_drC(k)
103     cL1 = (2. _d 0 -wCFL)*(1. _d 0 -wCFL)*oneSixth
104     cH3 = (1. _d 0 -wCFL*wCFL)*oneSixth
105     c cM2 = (1. _d 0 - wCFL)/( wCFL +1. _d -20)
106     cM2 = (1. _d 0 + wCFL)/( wCFL +1. _d -20)
107    
108     Rj =(tFld(i,j,k) -tFld(i,j,k-1))
109     IF ( rTrans(i,j).GT.0. _d 0 ) THEN
110     Rjh = (tFld(i,j,k-1)-tFld(i,j,km2))*maskC(i,j,km2,bi,bj)
111     ELSE
112     Rjh = (tFld(i,j,kp1)-tFld(i,j,k) )*maskC(i,j,kp1,bi,bj)
113     ENDIF
114     IF ( Rj*Rjh.LE.0. _d 0 ) THEN
115     C- 1rst case: theta < 0 (Rj & Rjh opposite sign) => Psi = 0
116     lowFac(i,j) = 0. _d 0
117     highFac(i,j)= 0. _d 0
118     ELSE
119     Rj = ABS(Rj)
120     Rjh = ABS(Rjh)
121     th1 = cL1*Rj+cH3*Rjh
122     th2 = cM2*Rjh
123     IF ( th1.LE.th2 .AND. th1.LE.Rj ) THEN
124     C- 2nd case: cL1+theta*cH3 = min of the three = Psi
125     lowFac(i,j) = cL1
126     highFac(i,j)= cH3
127     ELSEIF ( th2.LT.th1 .AND. th2.LE.Rj ) THEN
128     C- 3rd case: theta*cM2 = min of the three = Psi
129     lowFac(i,j) = 0. _d 0
130     highFac(i,j)= cM2
131     ELSE
132     C- 4th case (Rj < th1 & Rj < th2) : 1 = min of the three = Psi
133     lowFac(i,j) = 1. _d 0
134     highFac(i,j)= 0. _d 0
135     ENDIF
136     ENDIF
137     ENDDO
138     ENDDO
139    
140     C-- Add centered & upwind contributions
141     DO j=jMin,jMax
142     DO i=iMin,iMax
143     rCenter= 0.5 _d 0 *rTrans(i,j)*recip_rA(i,j,bi,bj)*rkSign
144     mskM = maskC(i,j,km2,bi,bj)*maskM2
145     mskP = maskC(i,j,kp1,bi,bj)*maskP1
146     rUpwind= (0.5 _d 0 -lowFac(i,j))*ABS(rCenter)*2. _d 0
147     rC4km = highFac(i,j)*(rCenter+ABS(rCenter))*mskM
148     rC4kp = highFac(i,j)*(rCenter-ABS(rCenter))*mskP
149    
150     a5d(i,j,k) = a5d(i,j,k)
151     & + rC4km
152     & *deltaTarg(k)
153     & *recip_hFacC(i,j,k,bi,bj)*recip_drF(k)
154     b5d(i,j,k) = b5d(i,j,k)
155     & - ( (rCenter+rUpwind) + rC4km )
156     & *deltaTarg(k)
157     & *recip_hFacC(i,j,k,bi,bj)*recip_drF(k)
158     c5d(i,j,k) = c5d(i,j,k)
159     & - ( (rCenter-rUpwind) + rC4kp )
160     & *deltaTarg(k)
161     & *recip_hFacC(i,j,k,bi,bj)*recip_drF(k)
162     d5d(i,j,k) = d5d(i,j,k)
163     & + rC4kp
164     & *deltaTarg(k)
165     & *recip_hFacC(i,j,k,bi,bj)*recip_drF(k)
166     b5d(i,j,k-1) = b5d(i,j,k-1)
167     & - rC4km
168     & *deltaTarg(k-1)
169     & *recip_hFacC(i,j,k-1,bi,bj)*recip_drF(k-1)
170     c5d(i,j,k-1) = c5d(i,j,k-1)
171     & + ( (rCenter+rUpwind) + rC4km )
172     & *deltaTarg(k-1)
173     & *recip_hFacC(i,j,k-1,bi,bj)*recip_drF(k-1)
174     d5d(i,j,k-1) = d5d(i,j,k-1)
175     & + ( (rCenter-rUpwind) + rC4kp )
176     & *deltaTarg(k-1)
177     & *recip_hFacC(i,j,k-1,bi,bj)*recip_drF(k-1)
178     e5d(i,j,k-1) = e5d(i,j,k-1)
179     & - rC4kp
180     & *deltaTarg(k-1)
181     & *recip_hFacC(i,j,k-1,bi,bj)*recip_drF(k-1)
182     ENDDO
183     ENDDO
184    
185     C-- process interior interface only: end
186     ENDIF
187    
188     RETURN
189     END

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