/[MITgcm]/MITgcm/pkg/generic_advdiff/gad_os7mp_adv_x.F
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Revision 1.4 - (show annotations) (download)
Fri May 11 17:30:06 2007 UTC (17 years ago) by adcroft
Branch: MAIN
Changes since 1.3: +11 -10 lines
Bug fix: added "Eps" to expressions deviding by cfl.
 - This singular expression was giving problems in the DOME experiments.

1 C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_os7mp_adv_x.F,v 1.3 2007/04/04 01:39:06 jmc Exp $
2 C $Name: $
3
4 #include "GAD_OPTIONS.h"
5
6 SUBROUTINE GAD_OS7MP_ADV_X(
7 I bi,bj,k, calcCFL, deltaTloc,
8 I uTrans, uFld,
9 I maskLocW, Q,
10 O uT,
11 I myThid )
12 C /==========================================================\
13 C | SUBROUTINE GAD_OS7MP_ADV_X |
14 C | o Compute Zonal advective Flux of tracer Q using |
15 C | 7th Order DST Sceheme with monotone preserving limiter |
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 LOGICAL calcCFL
27 _RL deltaTloc
28 _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
29 _RL uFld (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
30 _RS maskLocW(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
31 _RL Q (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 _RL cfl,Psi
38 _RL uLoc,Fac,Del,DelIp,DelI,Phi,Eps,rp1h,rp1h_cfl,Msk
39 _RL Qippp,Qipp,Qip,Qi,Qim,Qimm,Qimmm
40 _RL MskIpp,MskIp,MskI,MskIm,MskImm,MskImmm
41 _RL d2,d2p1,d2m1,A,B,C,D
42 _RL dp1h,dm1h,qMD,qUL,qLC,PhiMD,PhiLC,PhiMin,PhiMax
43
44 Eps = 1. _d -20
45
46 DO j=1-Oly,sNy+Oly
47 uT(1-Olx,j)=0. _d 0
48 uT(2-Olx,j)=0. _d 0
49 uT(3-Olx,j)=0. _d 0
50 uT(4-Olx,j)=0. _d 0
51 uT(sNx+Olx-2,j)=0. _d 0
52 uT(sNx+Olx-1,j)=0. _d 0
53 uT(sNx+Olx,j)=0. _d 0
54 DO i=1-Olx+4,sNx+Olx-3
55
56 uLoc = uFld(i,j)
57 cfl = uLoc
58 IF ( calcCFL ) cfl = abs(uLoc*deltaTloc*recip_dxC(i,j,bi,bj))
59
60 IF (uTrans(i,j).gt.0.) THEN
61 Qippp = Q(i+2,j)
62 Qipp = Q(i+1,j)
63 Qip = Q(i,j)
64 Qi = Q(i-1,j)
65 Qim = Q(i-2,j)
66 Qimm = Q(i-3,j)
67 Qimmm = Q(i-4,j)
68
69 MskIpp = maskLocW(i+2,j)
70 MskIp = maskLocW(i+1,j)
71 MskI = maskLocW(i,j)
72 MskIm = maskLocW(i-1,j)
73 MskImm = maskLocW(i-2,j)
74 MskImmm = maskLocW(i-3,j)
75 ELSEIF (uTrans(i,j).lt.0.) THEN
76 Qippp = Q(i-3,j)
77 Qipp = Q(i-2,j)
78 Qip = Q(i-1,j)
79 Qi = Q(i,j)
80 Qim = Q(i+1,j)
81 Qimm = Q(i+2,j)
82 Qimmm = Q(i+3,j)
83
84 MskIpp = maskLocW(i-2,j)
85 MskIp = maskLocW(i-1,j)
86 MskI = maskLocW(i,j)
87 MskIm = maskLocW(i+1,j)
88 MskImm = maskLocW(i+2,j)
89 MskImmm = maskLocW(i+3,j)
90 ENDIF
91
92 IF (uTrans(i,j).ne.0.) THEN
93 C 2nd order correction [i i-1]
94 Fac = 1.
95 Del = Qip-Qi
96 Msk = MskI
97 Phi = Msk * Fac * Del
98 C 3rd order correction [i i-1 i-2]
99 Fac = Fac * ( cfl + 1. )/3.
100 Del = Del - ( Qi-Qim )
101 Msk = Msk * MskIm
102 Phi = Phi - Msk * Fac * Del
103 C 4th order correction [i+1 i i-1 i-2]
104 Fac = Fac * ( cfl - 2. )/4.
105 Del = ( Qipp-2.*Qip+Qi ) - Del
106 Msk = Msk * MskIp
107 Phi = Phi + Msk * Fac * Del
108 C 5th order correction [i+1 i i-1 i-2 i-3]
109 Fac = Fac * ( cfl - 3. )/5.
110 Del = Del - ( Qip-3.*Qi+3.*Qim-Qimm )
111 Msk = Msk * MskImm
112 Phi = Phi + Msk * Fac * Del
113 C 6th order correction [i+2 i+1 i i-1 i-2 i-3]
114 Fac = Fac * ( cfl + 2. )/6.
115 Del = ( Qippp-4.*Qipp+6.*Qip-4.*Qi+Qim ) - Del
116 Msk = Msk * MskIpp
117 Phi = Phi + Msk * Fac * Del
118 C 7th order correction [i+2 i+1 i i-1 i-2 i-3 i-4]
119 Fac = Fac * ( cfl + 2. )/7.
120 Del = Del - ( Qipp-5.*Qip+10.*Qi-10.*Qim+5.*Qimm-Qimmm )
121 Msk = Msk * MskImmm
122 Phi = Phi - Msk * Fac * Del
123
124 DelIp = ( Qip - Qi ) * MskI
125 Phi = sign(1. _d 0,Phi)*sign(1. _d 0,DelIp)
126 & *abs(Phi+Eps)/abs(DelIp+Eps)
127
128 DelI = ( Qi - Qim ) * MskIm
129 rp1h =sign(1. _d 0,DelI)*sign(1. _d 0,DelIp)
130 & *abs(DelI+Eps)/abs(DelIp+Eps)
131 rp1h_cfl = rp1h/(cfl+Eps)
132
133 C TVD limiter
134 ! Phi = max(0. _d 0, min( 2./(1-cfl), Phi, 2.*rp1h_cfl ) )
135
136 C MP limiter
137 d2 = ( ( Qip + Qim ) - 2.*Qi ) * MskI * MskIm
138 d2p1 = ( ( Qipp + Qi ) - 2.*Qip ) * MskIp * MskI
139 d2m1 = ( ( Qi + Qimm ) - 2.*Qim ) * MskIm * MskImm
140 A = 4.*d2 - d2p1
141 B = 4.*d2p1 - d2
142 C = d2
143 D = d2p1;
144 dp1h = max(min(A,B,C,D),0. _d 0)+min(max(A,B,C,D),0. _d 0)
145 A = 4.*d2m1 - d2
146 B = 4.*d2 - d2m1
147 C = d2m1
148 D = d2;
149 dm1h = max(min(A,B,C,D),0. _d 0)+min(max(A,B,C,D),0. _d 0)
150 qMD = 0.5*( ( Qi + Qip ) - dp1h )
151 qUL = Qi + (1.-cfl)/(cfl+Eps)*( Qi-Qim )
152 qLC = Qi + 0.5*( 1.+dm1h/(Qi-Qim+Eps) )*(qUL-Qi)
153 PhiMD = 2./(1.-cfl)*(qMD-Qi+Eps)/(Qip-Qi+Eps)
154 PhiLC = 2.*rp1h_cfl*(qLC-Qi+Eps)/(qUL-Qi+Eps)
155 PhiMin = max(min(0. _d 0,PhiMD),
156 & min(0. _d 0,2.*rp1h_cfl,PhiLC))
157 PhiMax = min(max(2. _d 0/(1.-cfl),PhiMD),
158 & max(0. _d 0,2.*rp1h_cfl,PhiLC))
159 Phi = max(PhiMin,min(Phi,PhiMax))
160
161 Psi = Phi * 0.5 * (1. - cfl)
162 uT(i,j) = uTrans(i,j)*( Qi + Psi*DelIp )
163 ELSE
164 uT(i,j) = 0.
165 ENDIF
166
167 ENDDO
168 ENDDO
169
170 RETURN
171 END

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