| 1 |
C $Header: /u/gcmpack/MITgcm/pkg/mom_common/mom_u_bottomdrag.F,v 1.17 2015/01/04 16:16:32 jmc Exp $ |
| 2 |
C $Name: $ |
| 3 |
|
| 4 |
#include "MOM_COMMON_OPTIONS.h" |
| 5 |
#ifdef ALLOW_CTRL |
| 6 |
# include "CTRL_OPTIONS.h" |
| 7 |
#endif |
| 8 |
|
| 9 |
CBOP |
| 10 |
C !ROUTINE: MOM_U_BOTTOMDRAG |
| 11 |
|
| 12 |
C !INTERFACE: ========================================================== |
| 13 |
SUBROUTINE MOM_U_BOTTOMDRAG( |
| 14 |
I bi, bj, k, |
| 15 |
I uFld, vFld, KE, kappaRU, |
| 16 |
O uDragTerms, |
| 17 |
I myThid ) |
| 18 |
|
| 19 |
C !DESCRIPTION: |
| 20 |
C Calculates the drag due to friction and the no-slip condition at bottom: |
| 21 |
C \begin{equation*} |
| 22 |
C G^u_{drag} = - \frac{1}{\Delta r_f} ( r_b + C_D |v| + \frac{2}{\Delta r_c} ) u |
| 23 |
C \end{equation*} |
| 24 |
|
| 25 |
C !USES: =============================================================== |
| 26 |
IMPLICIT NONE |
| 27 |
#include "SIZE.h" |
| 28 |
#include "EEPARAMS.h" |
| 29 |
#include "PARAMS.h" |
| 30 |
#include "GRID.h" |
| 31 |
#ifdef ALLOW_CTRL |
| 32 |
# include "CTRL_FIELDS.h" |
| 33 |
#endif |
| 34 |
|
| 35 |
C !INPUT PARAMETERS: =================================================== |
| 36 |
C bi,bj :: tile indices |
| 37 |
C k :: vertical level |
| 38 |
C uFld :: zonal flow |
| 39 |
C vFld :: meridional flow |
| 40 |
C KE :: Kinetic energy |
| 41 |
C kappaRU :: vertical viscosity |
| 42 |
C myThid :: thread number |
| 43 |
INTEGER bi,bj,k |
| 44 |
_RL uFld(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
| 45 |
_RL vFld(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
| 46 |
_RL KE(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
| 47 |
_RL kappaRU(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr+1) |
| 48 |
INTEGER myThid |
| 49 |
|
| 50 |
C !OUTPUT PARAMETERS: ================================================== |
| 51 |
C uDragTerms :: drag term |
| 52 |
_RL uDragTerms(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
| 53 |
|
| 54 |
C !LOCAL VARIABLES: ==================================================== |
| 55 |
C i,j :: loop indices |
| 56 |
INTEGER i,j,kDown,kLowF,kBottom |
| 57 |
_RL viscFac, dragFac, uSq |
| 58 |
_RL recDrC |
| 59 |
_RL recDrF_bot(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
| 60 |
CEOP |
| 61 |
|
| 62 |
C- No-slip BCs impose a drag at bottom |
| 63 |
viscFac = 0. |
| 64 |
IF (no_slip_bottom) viscFac = 2. |
| 65 |
IF ( usingZCoords ) THEN |
| 66 |
kBottom = Nr |
| 67 |
kDown = MIN(k+1,Nr) |
| 68 |
kLowF = k+1 |
| 69 |
c dragFac = mass2rUnit*rhoConst |
| 70 |
c dragFac = wUnit2rVel(k+1) |
| 71 |
dragFac = 1. _d 0 |
| 72 |
ELSE |
| 73 |
kBottom = 1 |
| 74 |
kDown = MAX(k-1,1) |
| 75 |
kLowF = k |
| 76 |
dragFac = mass2rUnit*rhoConst |
| 77 |
c dragFac = wUnit2rVel(k) |
| 78 |
ENDIF |
| 79 |
IF ( k.EQ.kBottom ) THEN |
| 80 |
recDrC = recip_drF(k) |
| 81 |
DO j=1-OLy,sNy+OLy |
| 82 |
DO i=1-OLx,sNx+OLx |
| 83 |
recDrF_bot(i,j) = _recip_hFacW(i,j,k,bi,bj)*recip_drF(k) |
| 84 |
ENDDO |
| 85 |
ENDDO |
| 86 |
ELSE |
| 87 |
recDrC = recip_drC(kLowF) |
| 88 |
DO j=1-OLy,sNy+OLy |
| 89 |
DO i=1-OLx,sNx+OLx |
| 90 |
recDrF_bot(i,j) = _recip_hFacW(i,j,k,bi,bj)*recip_drF(k) |
| 91 |
& * ( 1. _d 0 -_maskW(i,j,kDown,bi,bj) ) |
| 92 |
ENDDO |
| 93 |
ENDDO |
| 94 |
ENDIF |
| 95 |
|
| 96 |
C-- Linear bottom drag: |
| 97 |
DO j=1-OLy,sNy+OLy-1 |
| 98 |
DO i=1-OLx+1,sNx+OLx-1 |
| 99 |
uDragTerms(i,j) = |
| 100 |
& - recDrF_bot(i,j) |
| 101 |
& *( bottomDragLinear*dragFac |
| 102 |
#ifdef ALLOW_BOTTOMDRAG_CONTROL |
| 103 |
& + halfRL*( bottomDragFld(i-1,j,bi,bj) |
| 104 |
& + bottomDragFld(i,j,bi,bj) )*dragFac |
| 105 |
#endif |
| 106 |
& ) |
| 107 |
#ifndef IMPLICIT_BOTTOMSIDEDRAG |
| 108 |
& * uFld(i,j) |
| 109 |
#endif |
| 110 |
ENDDO |
| 111 |
ENDDO |
| 112 |
|
| 113 |
C-- Add friction at the bottom (no-slip BC) |
| 114 |
IF ( no_slip_bottom .AND. bottomVisc_pCell ) THEN |
| 115 |
C- bottom friction accounts for true distance (including hFac) to the bottom |
| 116 |
DO j=1-OLy,sNy+OLy-1 |
| 117 |
DO i=1-OLx+1,sNx+OLx-1 |
| 118 |
uDragTerms(i,j) = uDragTerms(i,j) |
| 119 |
& - recDrF_bot(i,j) |
| 120 |
& *( kappaRU(i,j,kLowF)*recDrC*viscFac |
| 121 |
& *_recip_hFacW(i,j,k,bi,bj) |
| 122 |
& ) |
| 123 |
#ifndef IMPLICIT_BOTTOMSIDEDRAG |
| 124 |
& * uFld(i,j) |
| 125 |
#endif |
| 126 |
ENDDO |
| 127 |
ENDDO |
| 128 |
ELSEIF ( no_slip_bottom ) THEN |
| 129 |
C- ignores partial-cell reduction of the distance to the bottom |
| 130 |
DO j=1-OLy,sNy+OLy-1 |
| 131 |
DO i=1-OLx+1,sNx+OLx-1 |
| 132 |
uDragTerms(i,j) = uDragTerms(i,j) |
| 133 |
& - recDrF_bot(i,j) |
| 134 |
& *( kappaRU(i,j,kLowF)*recDrC*viscFac |
| 135 |
& ) |
| 136 |
#ifndef IMPLICIT_BOTTOMSIDEDRAG |
| 137 |
& * uFld(i,j) |
| 138 |
#endif |
| 139 |
ENDDO |
| 140 |
ENDDO |
| 141 |
ENDIF |
| 142 |
|
| 143 |
C-- Add quadratic bottom drag |
| 144 |
IF ( selectBotDragQuadr.EQ.0 ) THEN |
| 145 |
C- average grid-cell-center KE to get velocity norm @ U.pt |
| 146 |
DO j=1-OLy,sNy+OLy-1 |
| 147 |
DO i=1-OLx+1,sNx+OLx-1 |
| 148 |
IF ( (KE(i,j)+KE(i-1,j)) .GT. 0. ) THEN |
| 149 |
uDragTerms(i,j) = uDragTerms(i,j) |
| 150 |
& - recDrF_bot(i,j) |
| 151 |
& *bottomDragQuadratic*SQRT(KE(i,j)+KE(i-1,j))*dragFac |
| 152 |
#ifndef IMPLICIT_BOTTOMSIDEDRAG |
| 153 |
& * uFld(i,j) |
| 154 |
#endif |
| 155 |
ENDIF |
| 156 |
ENDDO |
| 157 |
ENDDO |
| 158 |
ELSEIF ( selectBotDragQuadr.EQ.1 ) THEN |
| 159 |
C- calculate locally velocity norm @ U.pt (local U & 4 V averaged) |
| 160 |
DO j=1-OLy,sNy+OLy-1 |
| 161 |
DO i=1-OLx+1,sNx+OLx-1 |
| 162 |
uSq = uFld(i,j)*uFld(i,j) |
| 163 |
& + ( (vFld(i-1, j )*vFld(i-1, j )*hFacS(i-1, j ,k,bi,bj) |
| 164 |
& +vFld( i , j )*vFld( i , j )*hFacS( i , j ,k,bi,bj)) |
| 165 |
& + (vFld(i-1,j+1)*vFld(i-1,j+1)*hFacS(i-1,j+1,k,bi,bj) |
| 166 |
& +vFld( i ,j+1)*vFld( i ,j+1)*hFacS( i ,j+1,k,bi,bj)) |
| 167 |
& )*recip_hFacW(i,j,k,bi,bj)*0.25 _d 0 |
| 168 |
IF ( uSq.GT.zeroRL ) THEN |
| 169 |
uDragTerms(i,j) = uDragTerms(i,j) |
| 170 |
& - recDrF_bot(i,j) |
| 171 |
& *bottomDragQuadratic*SQRT(uSq)*dragFac |
| 172 |
#ifndef IMPLICIT_BOTTOMSIDEDRAG |
| 173 |
& * uFld(i,j) |
| 174 |
#endif |
| 175 |
ENDIF |
| 176 |
ENDDO |
| 177 |
ENDDO |
| 178 |
ELSEIF ( selectBotDragQuadr.EQ.2 ) THEN |
| 179 |
C- same as above but using wet-point method to average 4 V |
| 180 |
DO j=1-OLy,sNy+OLy-1 |
| 181 |
DO i=1-OLx+1,sNx+OLx-1 |
| 182 |
uSq = ( hFacS(i-1, j ,k,bi,bj) + hFacS( i , j ,k,bi,bj) ) |
| 183 |
& + ( hFacS(i-1,j+1,k,bi,bj) + hFacS( i ,j+1,k,bi,bj) ) |
| 184 |
IF ( uSq.GT.zeroRL ) THEN |
| 185 |
uSq = uFld(i,j)*uFld(i,j) |
| 186 |
& +( (vFld(i-1, j )*vFld(i-1, j )*hFacS(i-1, j ,k,bi,bj) |
| 187 |
& +vFld( i , j )*vFld( i , j )*hFacS( i , j ,k,bi,bj)) |
| 188 |
& + (vFld(i-1,j+1)*vFld(i-1,j+1)*hFacS(i-1,j+1,k,bi,bj) |
| 189 |
& +vFld( i ,j+1)*vFld( i ,j+1)*hFacS( i ,j+1,k,bi,bj)) |
| 190 |
& )/uSq |
| 191 |
ELSE |
| 192 |
uSq = uFld(i,j)*uFld(i,j) |
| 193 |
ENDIF |
| 194 |
IF ( uSq.GT.zeroRL ) THEN |
| 195 |
uDragTerms(i,j) = uDragTerms(i,j) |
| 196 |
& - recDrF_bot(i,j) |
| 197 |
& *bottomDragQuadratic*SQRT(uSq)*dragFac |
| 198 |
#ifndef IMPLICIT_BOTTOMSIDEDRAG |
| 199 |
& * uFld(i,j) |
| 200 |
#endif |
| 201 |
ENDIF |
| 202 |
ENDDO |
| 203 |
ENDDO |
| 204 |
ELSEIF ( selectBotDragQuadr.NE.-1 ) THEN |
| 205 |
STOP 'MOM_U_BOTTOMDRAG: invalid selectBotDragQuadr value' |
| 206 |
ENDIF |
| 207 |
|
| 208 |
#ifdef IMPLICIT_BOTTOMSIDEDRAG |
| 209 |
DO j=1-OLy+1,sNy+OLy-1 |
| 210 |
DO i=1-OLx,sNx+OLx-1 |
| 211 |
uDragTerms(i,j) = uDragTerms(i,j)*uFld(i,j) / |
| 212 |
& (1. - deltaTmom*uDragTerms(i,j)) |
| 213 |
ENDDO |
| 214 |
ENDDO |
| 215 |
#endif |
| 216 |
|
| 217 |
#ifdef ALLOW_DIAGNOSTICS |
| 218 |
IF (useDiagnostics) THEN |
| 219 |
CALL DIAGNOSTICS_FILL(uDragTerms,'UBotDrag',k,1,2,bi,bj,myThid) |
| 220 |
ENDIF |
| 221 |
#endif /* ALLOW_DIAGNOSTICS */ |
| 222 |
|
| 223 |
RETURN |
| 224 |
END |
Parent Directory
| 
Revision Log
| 
Revision Graph