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C $Header: /u/gcmpack/MITgcm/pkg/mom_fluxform/mom_cdscheme.F,v 1.5 2003/02/09 02:01:49 jmc Exp $ |
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C $Name: $ |
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|
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#include "CPP_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: MOM_CDSCHEME |
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|
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C !INTERFACE: ========================================================== |
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SUBROUTINE MOM_CDSCHEME( |
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I bi,bj,k,dPhiHydX,dPhiHydY, |
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I myThid) |
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|
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C !DESCRIPTION: |
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C The C-D scheme. The less said the better :-) |
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|
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C !USES: =============================================================== |
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C == Global variables == |
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IMPLICIT NONE |
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#include "SIZE.h" |
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#include "DYNVARS.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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#include "SURFACE.h" |
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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 dPhiHydX,Y :: Gradient (X & Y dir.) of Hydrostatic Potential |
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C myThid :: thread number |
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INTEGER bi,bj,k |
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_RL dPhiHydX(1-Olx:sNx+Olx,1-Oly:sNy+Oly) |
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_RL dPhiHydY(1-Olx:sNx+Olx,1-Oly:sNy+Oly) |
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INTEGER myThid |
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|
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|
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C !LOCAL VARIABLES: ==================================================== |
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#ifdef INCLUDE_CD_CODE |
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C i,j :: loop indices |
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C pF :: pressure gradient |
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C vF :: work space |
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C aF :: work space |
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_RL pF(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL vF(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL aF(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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INTEGER i,j,iMin,iMax,jMin,jMax |
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_RL ab15,ab05 |
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_RL phxFac, phyFac |
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CEOP |
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|
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C Compute ranges |
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iMin=1-Olx+1 |
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iMax=sNx+Olx-1 |
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jMin=1-Oly+1 |
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jMax=sNy+Oly-1 |
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|
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C Adams-Bashforth weighting factors |
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ab15 = 1.5 + abEps |
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ab05 = -0.5 - abEps |
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|
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C-- stagger time stepping: grad Phi_Hyp is not in gU,gV and needs to be added: |
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IF (staggerTimeStep) THEN |
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phxFac = pfFacMom |
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phyFac = pfFacMom |
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ELSE |
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phxFac = 0. |
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phyFac = 0. |
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ENDIF |
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|
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C Pressure extrapolated forward in time |
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DO j=1-Oly,sNy+Oly |
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DO i=1-Olx,sNx+Olx |
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pf(i,j) = |
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& ab15*( etaN(i,j,bi,bj)*Bo_surf(i,j,bi,bj) ) |
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& +ab05*(etaNm1(i,j,bi,bj)*Bo_surf(i,j,bi,bj) ) |
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ENDDO |
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ENDDO |
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|
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C-- Zonal velocity coriolis term |
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C Note. As coded here, coriolis will not work with "thin walls" |
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C-- Coriolis with CD scheme allowed |
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C grady(p) + gV |
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DO j=1-Oly+1,sNy+Oly |
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DO i=1-Olx,sNx+Olx |
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af(i,j) = -_maskS(i,j,k,bi,bj)*( |
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& _recip_dyC(i,j,bi,bj)*(pf(i,j)-pf(i,j-1)) |
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& +phyFac*dPhiHydY(i,j) ) |
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& + gV(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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C Average to Vd point and add coriolis |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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vf(i,j) = |
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& 0.25*( af(i ,j)+af(i ,j+1) |
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& +af(i-1,j)+af(i-1,j+1) |
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& )*_maskW(i,j,k,bi,bj) |
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& -0.5*(_fCori(i,j,bi,bj)+ |
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& _fCori(i-1,j,bi,bj)) |
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& *uVel(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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C Step forward Vd |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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vVelD(i,j,k,bi,bj) = vVelD(i,j,k,bi,bj) + |
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& deltaTmom*vf(i,j) |
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ENDDO |
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ENDDO |
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C Relax D grid V to C grid V |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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vVelD(i,j,k,bi,bj) = rCD*vVelD(i,j,k,bi,bj) |
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& +(1. - rCD)*( |
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& ab15*0.25*( |
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& vVel(i ,j ,k,bi,bj)+vVel(i ,j+1,k,bi,bj) |
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& +vVel(i-1,j ,k,bi,bj)+vVel(i-1,j+1,k,bi,bj) |
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& )*_maskW(i,j,k,bi,bj) |
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& + |
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& ab05*0.25*( |
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& vNM1(i ,j ,k,bi,bj)+vNM1(i ,j+1,k,bi,bj) |
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& +vNM1(i-1,j ,k,bi,bj)+vNM1(i-1,j+1,k,bi,bj) |
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& )*_maskW(i,j,k,bi,bj) |
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& ) |
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ENDDO |
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ENDDO |
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C Calculate coriolis force on U |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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guCD(i,j,k,bi,bj) = |
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& 0.5*( _fCori(i ,j,bi,bj) + |
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& _fCori(i-1,j,bi,bj) ) |
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& *vVelD(i,j,k,bi,bj)*cfFacMom |
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ENDDO |
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ENDDO |
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|
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C-- Meridional velocity coriolis term |
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C gradx(p)+gU |
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DO j=1-Oly,sNy+Oly |
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DO i=1-Olx+1,sNx+Olx |
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af(i,j) = -_maskW(i,j,k,bi,bj)*( |
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& _recip_dxC(i,j,bi,bj)*(pf(i,j)-pf(i-1,j)) |
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& +phxFac*dPhiHydX(i,j) ) |
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& + gU(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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C Average to Ud point and add coriolis |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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vf(i,j) = |
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& 0.25*( af(i ,j)+af(i ,j-1) |
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& +af(i+1,j)+af(i+1,j-1) |
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& )*_maskS(i,j,k,bi,bj) |
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& +0.5*( _fCori(i,j,bi,bj) |
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& +_fCori(i,j-1,bi,bj)) |
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& *vVel(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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C Step forward Ud |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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uVelD(i,j,k,bi,bj) = uVelD(i,j,k,bi,bj) + |
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& deltaTmom*vf(i,j)*_maskS(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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C Relax D grid U to C grid U |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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uVelD(i,j,k,bi,bj) = rCD*uVelD(i,j,k,bi,bj) |
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& +(1. - rCD)*( |
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& ab15*0.25*( |
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& uVel(i,j ,k,bi,bj)+uVel(i+1,j ,k,bi,bj) |
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& +uVel(i,j-1,k,bi,bj)+uVel(i+1,j-1,k,bi,bj) |
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& )*_maskS(i,j,k,bi,bj) |
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& + |
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& ab05*0.25*( |
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& uNM1(i,j ,k,bi,bj)+uNM1(i+1,j ,k,bi,bj) |
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& +uNM1(i,j-1,k,bi,bj)+uNM1(i+1,j-1,k,bi,bj) |
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& )*_maskS(i,j,k,bi,bj) |
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& ) |
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ENDDO |
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ENDDO |
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C Calculate coriolis force on V |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gvCD(i,j,k,bi,bj) = |
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& -0.5*( _fCori(i ,j,bi,bj) |
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& +_fCori(i,j-1,bi,bj) ) |
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& *uVelD(i,j,k,bi,bj)*_maskS(i,j,k,bi,bj)*cfFacMom |
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ENDDO |
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ENDDO |
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|
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C-- Save "previous time level" variables |
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DO j=1-OLy,sNy+OLy |
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DO i=1-OLx,sNx+OLx |
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uNM1(i,j,k,bi,bj) = uVel(i,j,k,bi,bj) |
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vNM1(i,j,k,bi,bj) = vVel(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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|
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#endif /* INCLUDE_CD_CODE */ |
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|
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RETURN |
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END |
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