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C $Header: /u/gcmpack/MITgcm/pkg/seaice/seaice_calc_viscosities.F,v 1.23 2013/04/23 09:53:44 mlosch Exp $ |
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C $Name: $ |
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|
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#include "SEAICE_OPTIONS.h" |
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|
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CBOP |
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CStartOfInterface |
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SUBROUTINE SEAICE_CALC_VISCOSITIES( |
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I e11, e22, e12, zMin, zMax, hEffM, press0, |
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O eta, etaZ, zeta, press, |
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I iStep, myTime, myIter, myThid ) |
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C *==========================================================* |
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C | SUBROUTINE SEAICE_CALC_VISCOSITIES | |
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C | o compute shear and bulk viscositites eta, zeta and the | |
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C | corrected ice strength P | |
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C | (see Zhang and Hibler, JGR, 102, 8691-8702, 1997) | |
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C *==========================================================* |
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C | written by Martin Losch, Mar 2006 | |
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C *==========================================================* |
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IMPLICIT NONE |
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|
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C === Global variables === |
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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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#include "SEAICE_SIZE.h" |
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#include "SEAICE_PARAMS.h" |
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|
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#ifdef ALLOW_AUTODIFF_TAMC |
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# include "tamc.h" |
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#endif |
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|
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C === Routine arguments === |
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C iStep :: Sub-time-step number |
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C myTime :: Simulation time |
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C myIter :: Simulation timestep number |
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C myThid :: My Thread Id. number |
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INTEGER iStep |
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_RL myTime |
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INTEGER myIter |
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INTEGER myThid |
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C strain rate tensor |
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_RL e11 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL e22 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL e12 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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C |
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_RL zMin (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL zMax (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL hEffM (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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C |
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_RL press0(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL press (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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C bulk viscosity |
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_RL eta (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL etaZ (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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C shear viscosity |
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_RL zeta (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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CEndOfInterface |
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|
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#if ( defined (SEAICE_CGRID) && defined (SEAICE_ALLOW_DYNAMICS) ) |
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C === Local variables === |
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C i,j,bi,bj - Loop counters |
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C e11, e12, e22 - components of strain rate tensor |
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C ecm2 - inverse of square of eccentricity of yield curve |
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INTEGER i, j, bi, bj |
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_RL ECM2, deltaC, deltaCreg, tmp |
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_RL e12Csqr(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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#ifdef SEAICE_ALLOW_TEM |
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_RL etaMax, etaDen |
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#endif /* SEAICE_ALLOW_TEM */ |
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INTEGER k |
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_RL sumNorm |
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#ifdef SEAICE_ZETA_SMOOTHREG |
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_RL argTmp |
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#endif /* SEAICE_ZETA_SMOOTHREG */ |
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CEOP |
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|
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C-- FIRST SET UP BASIC CONSTANTS |
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k=1 |
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ecm2=0. _d 0 |
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IF ( SEAICE_eccen .NE. 0. _d 0 ) ecm2=ONE/(SEAICE_eccen**2) |
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C |
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DO bj=myByLo(myThid),myByHi(myThid) |
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DO bi=myBxLo(myThid),myBxHi(myThid) |
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C need to do this beforehand for easier vectorization after |
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C TAFization |
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IF ( SEAICEetaZmethod .EQ. 0 ) THEN |
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DO j=1-OLy+1,sNy+OLy-1 |
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DO i=1-OLx+1,sNx+OLx-1 |
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tmp = 0.25 * |
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& ( e12(I,J ,bi,bj) + e12(I+1,J ,bi,bj) |
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& + e12(I,J+1,bi,bj) + e12(I+1,J+1,bi,bj) ) |
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e12Csqr(i,j) = tmp*tmp |
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ENDDO |
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ENDDO |
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ELSEIF ( SEAICEetaZmethod .EQ. 3 ) THEN |
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DO j=1-OLy+1,sNy+OLy-1 |
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DO i=1-OLx+1,sNx+OLx-1 |
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C area weighted average of the squares of e12 is more accurate |
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C (and energy conserving) |
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e12Csqr(i,j) = 0.25 _d 0 * recip_rA(I,J,bi,bj) * |
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& ( rAz(I ,J ,bi,bj)*e12(I ,J ,bi,bj)**2 |
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& + rAz(I+1,J ,bi,bj)*e12(I+1,J ,bi,bj)**2 |
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& + rAz(I ,J+1,bi,bj)*e12(I ,J+1,bi,bj)**2 |
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& + rAz(I+1,J+1,bi,bj)*e12(I+1,J+1,bi,bj)**2 ) |
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ENDDO |
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ENDDO |
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ENDIF |
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DO j=1-OLy+1,sNy+OLy-1 |
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DO i=1-OLx+1,sNx+OLx-1 |
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deltaC = (e11(i,j,bi,bj)**2+e22(i,j,bi,bj)**2)*(ONE+ecm2) |
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& + 4. _d 0*ecm2*e12Csqr(i,j) |
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& + 2. _d 0*e11(i,j,bi,bj)*e22(i,j,bi,bj)*(ONE-ecm2) |
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#ifdef ALLOW_AUTODIFF_TAMC |
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C avoid sqrt of 0 |
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IF ( deltaC .GT. 0. _d 0 ) deltaC = SQRT(deltaC) |
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#else |
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deltaC = SQRT(deltaC) |
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#endif /* ALLOW_AUTODIFF_TAMC */ |
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deltaCreg = MAX(deltaC,SEAICE_EPS) |
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C "replacement pressure" |
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zeta (I,J,bi,bj) = HALF*press0(I,J,bi,bj)/deltaCreg |
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C put min and max viscosities in |
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#ifdef SEAICE_ZETA_SMOOTHREG |
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C regularize zeta to zmax with a smooth tanh-function instead |
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C of a min(zeta,zmax). This improves convergence of iterative |
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C solvers (Lemieux and Tremblay 2009, JGR). No effect on EVP |
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argTmp = exp(-1. _d 0/(deltaCreg*SEAICE_zetaMaxFac)) |
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zeta (I,J,bi,bj) = ZMAX(I,J,bi,bj) |
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& *(1. _d 0 - argTmp)/(1. _d 0 + argTmp) |
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#else |
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zeta (I,J,bi,bj) = MIN(ZMAX(I,J,bi,bj),zeta(I,J,bi,bj)) |
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#endif /* SEAICE_ZETA_SMOOTHREG */ |
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zeta (I,J,bi,bj) = MAX(ZMIN(I,J,bi,bj),zeta(I,J,bi,bj)) |
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C set viscosities to zero at hEffM flow pts |
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zeta (I,J,bi,bj) = zeta(I,J,bi,bj)*HEFFM(I,J,bi,bj) |
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eta (I,J,bi,bj) = ECM2*zeta(I,J,bi,bj) |
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press(I,J,bi,bj) = TWO *zeta(I,J,bi,bj)*deltaC |
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ENDDO |
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ENDDO |
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#ifdef SEAICE_ALLOW_TEM |
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IF ( SEAICEuseTEM ) THEN |
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DO j=1-OLy+1,sNy+OLy-1 |
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DO i=1-OLx+1,sNx+OLx-1 |
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etaDen = (e11(I,J,bi,bj)-e22(I,J,bi,bj))**2 |
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& + 4. _d 0*e12Csqr(i,j) |
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etaDen = SQRT(MAX(SEAICE_EPS_SQ,etaDen)) |
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etaMax = ( 0.5 _d 0*press(I,J,bi,bj)-zeta(I,J,bi,bj) |
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& *( e11(I,J,bi,bj)+e22(I,J,bi,bj) ) |
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& )/etaDen |
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eta(I,J,bi,bj) = MIN(eta(I,J,bi,bj),etaMax) |
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ENDDO |
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ENDDO |
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ENDIF |
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#endif /* SEAICE_ALLOW_TEM */ |
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C compute eta at Z-points by simple averaging |
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DO j=1-OLy+1,sNy+OLy-1 |
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DO i=1-OLx+1,sNx+OLx-1 |
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sumNorm = maskC(I,J, k,bi,bj)+maskC(I-1,J, k,bi,bj) |
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& + maskC(I,J-1,k,bi,bj)+maskC(I-1,J-1,k,bi,bj) |
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IF ( sumNorm.GT.0. _d 0 ) sumNorm = 1. _d 0 / sumNorm |
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etaZ(I,J,bi,bj) = sumNorm * |
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& ( eta (I,J ,bi,bj) + eta (I-1,J ,bi,bj) |
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& + eta (I,J-1,bi,bj) + eta (I-1,J-1,bi,bj) ) |
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ENDDO |
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ENDDO |
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C free-slip means no lateral stress, which is best achieved masking |
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C eta on vorticity(=Z)-points; from now on we only need to worry |
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C about the no-slip boundary conditions |
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IF (.NOT.SEAICE_no_slip) THEN |
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DO J=1-OLy+1,sNy+OLy-1 |
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DO I=1-OLx+1,sNx+OLx-1 |
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etaZ(I,J,bi,bj) = etaZ(I,J,bi,bj) |
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& *maskC(I,J, k,bi,bj)*maskC(I-1,J, k,bi,bj) |
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& *maskC(I,J-1,k,bi,bj)*maskC(I-1,J-1,k,bi,bj) |
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ENDDO |
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ENDDO |
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ENDIF |
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ENDDO |
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ENDDO |
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|
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#endif /* SEAICE_ALLOW_DYNAMICS and SEAICE_CGRID */ |
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RETURN |
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END |
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