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C $Header: /u/gcmpack/MITgcm/pkg/mom_common/mom_u_bottomdrag.F,v 1.8 2008/10/20 21:40:22 jmc Exp $ |
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C $Name: $ |
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|
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#include "MOM_COMMON_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: MOM_U_BOTTOMDRAG |
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|
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C !INTERFACE: ========================================================== |
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SUBROUTINE MOM_U_BOTTOMDRAG( |
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I bi,bj,k, |
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I uFld, KE, KappaRU, |
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O uDragTerms, |
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I myThid) |
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|
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C !DESCRIPTION: |
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C Calculates the drag due to friction and the no-slip condition at bottom: |
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C \begin{equation*} |
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C G^u_{drag} = - \frac{1}{\Delta r_f} ( r_b + C_D |v| + \frac{2}{\Delta r_c} ) u |
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C \end{equation*} |
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|
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C !USES: =============================================================== |
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IMPLICIT NONE |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "PARAMS.h" |
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#include "GRID.h" |
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#ifdef ALLOW_BOTTOMDRAG_CONTROL |
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# include "DYNVARS.h" |
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#endif |
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|
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C !INPUT PARAMETERS: =================================================== |
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C bi,bj :: tile indices |
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C k :: vertical level |
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C uFld :: zonal flow |
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C KE :: Kinetic energy |
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C KappaRU :: vertical viscosity |
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C myThid :: thread number |
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INTEGER bi,bj,k |
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_RL uFld(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL KE(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL KappaRU(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr) |
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INTEGER myThid |
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|
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C !OUTPUT PARAMETERS: ================================================== |
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C uDragTerms :: drag term |
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_RL uDragTerms(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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|
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C !LOCAL VARIABLES: ==================================================== |
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C i,j :: loop indices |
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C Kp1 :: =k+1 for k<Nr, =Nr for k>=Nr |
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INTEGER i,j,kDown,kDownC,kBottom |
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_RL viscFac, dragFac |
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_RL rdrckp1, maskDown |
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CEOP |
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|
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C- No-slip BCs impose a drag at bottom |
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IF ( usingZCoords ) THEN |
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kBottom = Nr |
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kDown = min(k+1,kBottom) |
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kDownC = kDown |
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c dragFac = mass2rUnit*rhoConst |
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c dragFac = wUnit2rVel(k+1) |
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dragFac = 1. _d 0 |
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ELSE |
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kBottom = 1 |
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kDown = max(k-1,kBottom) |
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kDownC = k |
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dragFac = mass2rUnit*rhoConst |
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c dragFac = wUnit2rVel(k) |
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ENDIF |
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rdrckp1=recip_drC(kDownC) |
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IF (k.EQ.kBottom) rdrckp1=recip_drF(k) |
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viscFac=0. |
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IF (no_slip_bottom) viscFac=1. |
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DO j=1-Oly,sNy+Oly-1 |
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DO i=1-Olx+1,sNx+Olx-1 |
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maskDown=_maskW(i,j,kDown,bi,bj) |
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IF (k.EQ.kBottom) maskDown=0. |
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uDragTerms(i,j)= |
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& -_recip_hFacW(i,j,k,bi,bj)*recip_drF(k) |
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& *( |
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& 2.*KappaRU(i,j,kDownC)*rdrckp1*viscFac |
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#ifdef ALLOW_BOTTOMDRAG_CONTROL |
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& + bottomdragfld(i,j,bi,bj)*dragFac |
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#else |
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& + bottomDragLinear*dragFac |
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#endif |
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& )*(1.-maskDown)*uFld(i,j) |
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IF ( (KE(i,j)+KE(i-1,j)) .NE. 0. ) THEN |
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uDragTerms(i,j)=uDragTerms(i,j) |
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& -_recip_hFacW(i,j,k,bi,bj)*recip_drF(k) |
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& *bottomDragQuadratic*SQRT(KE(i,j)+KE(i-1,j))*dragFac |
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& *(1.-maskDown)*uFld(i,j) |
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ENDIF |
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ENDDO |
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ENDDO |
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|
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#ifdef ALLOW_DIAGNOSTICS |
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IF (useDiagnostics) THEN |
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CALL DIAGNOSTICS_FILL(uDragTerms,'UBotDrag',k,1,2,bi,bj,myThid) |
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ENDIF |
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#endif /* ALLOW_DIAGNOSTICS */ |
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|
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RETURN |
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END |
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