From babc30a98c08f0c21aee02ed2228c45ac100d1ab Mon Sep 17 00:00:00 2001 From: Robert Hallberg Date: Wed, 4 Dec 2019 15:24:10 -0500 Subject: [PATCH] (*)Correct dimensionally inconsistent advective CFL Corrects the dimensionally inconsistent expressions for the CFL number in the tracer advection code, in which a negligible thickness had been added to the cell volume to avoid division by zero. This change does not alter the solutions in the MOM6-examples test cases, but now it permits dimensional rescaling of lengths over a much larger range, and it could change answers if the minimum layer thicknesses are small enough. --- src/tracer/MOM_tracer_advect.F90 | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/src/tracer/MOM_tracer_advect.F90 b/src/tracer/MOM_tracer_advect.F90 index e050933dc2..e425629c77 100644 --- a/src/tracer/MOM_tracer_advect.F90 +++ b/src/tracer/MOM_tracer_advect.F90 @@ -485,8 +485,8 @@ subroutine advect_x(Tr, hprev, uhr, uh_neglect, OBC, domore_u, ntr, Idt, & else uhh(I) = uhr(I,j,k) endif - !ts2(I) = 0.5*(1.0 + uhh(I)/(hprev(i+1,j,k)+h_neglect)) - CFL(I) = - uhh(I)/(hprev(i+1,j,k)+h_neglect) ! CFL is positive + !ts2(I) = 0.5*(1.0 + uhh(I) / (hprev(i+1,j,k) + h_neglect*G%areaT(i+1,j))) + CFL(I) = - uhh(I) / (hprev(i+1,j,k) + h_neglect*G%areaT(i+1,j)) ! CFL is positive else hup = hprev(i,j,k) - G%areaT(i,j)*min_h hlos = MAX(0.0,-uhr(I-1,j,k)) @@ -497,8 +497,8 @@ subroutine advect_x(Tr, hprev, uhr, uh_neglect, OBC, domore_u, ntr, Idt, & else uhh(I) = uhr(I,j,k) endif - !ts2(I) = 0.5*(1.0 - uhh(I)/(hprev(i,j,k)+h_neglect)) - CFL(I) = uhh(I)/(hprev(i,j,k)+h_neglect) ! CFL is positive + !ts2(I) = 0.5*(1.0 - uhh(I) / (hprev(i,j,k) + h_neglect*G%areaT(i,j))) + CFL(I) = uhh(I) / (hprev(i,j,k) + h_neglect*G%areaT(i,j)) ! CFL is positive endif enddo @@ -573,7 +573,7 @@ subroutine advect_x(Tr, hprev, uhr, uh_neglect, OBC, domore_u, ntr, Idt, & ! Original implementation of PLM !flux_x(I,m) = uhh(I)*(Tr(m)%t(i+1,j,k) - slope_x(i+1,m)*ts2(I)) endif - !ts2(I) = 0.5*(1.0 - uhh(I)/(hprev(i,j,k)+h_neglect)) + !ts2(I) = 0.5*(1.0 - uhh(I)/(hprev(i,j,k)+h_neglect*G%areaT(i,j))) enddo ; enddo endif ! usePPM @@ -856,8 +856,8 @@ subroutine advect_y(Tr, hprev, vhr, vh_neglect, OBC, domore_v, ntr, Idt, & else vhh(i,J) = vhr(i,J,k) endif - !ts2(i) = 0.5*(1.0 + vhh(i,J) / (hprev(i,j+1,k)+h_neglect)) - CFL(i) = - vhh(i,J) / (hprev(i,j+1,k)+h_neglect) ! CFL is positive + !ts2(i) = 0.5*(1.0 + vhh(i,J) / (hprev(i,j+1,k) + h_neglect*G%areaT(i,j+1)) + CFL(i) = - vhh(i,J) / (hprev(i,j+1,k) + h_neglect*G%areaT(i,j+1)) ! CFL is positive else hup = hprev(i,j,k) - G%areaT(i,j)*min_h hlos = MAX(0.0,-vhr(i,J-1,k)) @@ -868,8 +868,8 @@ subroutine advect_y(Tr, hprev, vhr, vh_neglect, OBC, domore_v, ntr, Idt, & else vhh(i,J) = vhr(i,J,k) endif - !ts2(i) = 0.5*(1.0 - vhh(i,J) / (hprev(i,j,k)+h_neglect)) - CFL(i) = vhh(i,J) / (hprev(i,j,k)+h_neglect) ! CFL is positive + !ts2(i) = 0.5*(1.0 - vhh(i,J) / (hprev(i,j,k) + h_neglect*G%areaT(i,j))) + CFL(i) = vhh(i,J) / (hprev(i,j,k) + h_neglect*G%areaT(i,j)) ! CFL is positive endif enddo