Opened 13 years ago

Closed 13 years ago

# ldf coefficient

Reported by:reporter: Owned by:owner: The author of the ticket. Person in charge for handling rblod ctlod normal OCE release-2

### Description

Flyspray 79:
When the lateral mixing coefficient on the dynamics is a function of x,y (key_dynldf_c2d) the mixing coefficient is made proportional to grid spacing (if laplacian) or the cube of grid spacing (if bilaplacian). Logically, the same should be done for the mixing coefficient on tracers when key_ldftra_c2d is active. This is not what is done in ldftra_c2d.h90: for the biharmonic it is OK but the laplacian is left constant. This in not a bug but rather an inconsistency; however it lingers in the code (maybe we mentioned it a long time ago before flyspray was in operation?) I attach the DRAKKAR version of the routine.

Flysrapy 75:
2 things to do: # make the coefficients ahm & aht proportional to Dx/Dx3 for Laplacian/Bi?-Laplacian operator in routines ldf[tra/dyn]_c[2/3]d.h90 # in doing that, we must avoid numerical problems in the case of strong anisotropy (in north side), take the MAX(e1[tuv],e2[tuv]) of the scale factor in both direction as below for the Laplacian in ldftra_c2d.h90 ! proportionnal to the maximum grid spacing

zdx_max = MAXVAL( e1t(:, )

IF( lk_mpp ) CALL mpp_max( zdx_max ) ! max over the global domain
za00 = aht0 / ( zdx_max )

DO jj = 1, jpj

DO ji = 1, jpi
zeumax = MAX( e1u(ji,jj), e2u(ji,jj) )
zevmax = MAX( e1v(ji,jj), e2v(ji,jj) )
zetmax = MAX( e1t(ji,jj), e2t(ji,jj) )
ahtu(ji,jj) = za00 * zeumax ! set ahtu = ahtv at u- and v-points,
ahtv(ji,jj) = za00 * zevmax ! and ahtw at w-point (idem T-point)
ahtw(ji,jj) = za00 * zetmax !
END DO

END DO

### Commit History (1)

ChangesetTimeChangeLog
901rblod2008-04-22T21:16:18+02:00

Change ldf computation to take into account the grid anisotropy, see ticket #115

### comment:1 Changed 13 years ago by ctlod

• Owner changed from NEMO team to ctlod
• Status changed from new to assigned
• Summary changed from ldf coeeficient to ldf coefficient

### comment:2 Changed 13 years ago by rblod

• Resolution set to fixed
• Status changed from assigned to closed
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