Create a sponge layer

[matias.dinapoli]

Hello, I'm trying to set a sponge layer in the western and eastern edge. So I modified ana_sponge:

Code: Select all

        width=20.0_r8                !20 == 200 km

        MIXING(ng) % visc2_r(IstrT:IendT,JstrT:JendT)=0.0_r8
        MIXING(ng) % visc2_p(IstrT:IendT,JstrT:JendT)=0.0_r8
!
!  Eastern edge.
!
      DO i=MAX(IstrT,Lm(ng)+1-INT(width)),IendT
        DO j=JstrT,JendT
          MIXING(ng) % visc2_r(i,j)=50.0_r8
          MIXING(ng) % visc2_p(i,j)=50.0_r8
        END DO
      END DO

and in ocean.in:

Code: Select all

VISC2 == 0.0d0                           ! m2/s
VISC4 == 0.0d0                           ! m4/s

    LuvSponge == T                              ! horizontal momentum
LtracerSponge == F F                            ! temperature, salinity, inert

But, I compare the fields with and with out sponge, and I get the same results. I didn't set visc2 because I fix its value for each grid point in ana_sponge. Is there any option to see the value of the viscosity at each point? To check that ROMS do I what I want.

[arango]

I did a major overhaul of the sponge areas in ROMS sometime ago. We can have now visc_factor and diff_factor in the Grid NetCDF file. This is the way all application (simple or complex) that require areas of enhanced viscosity and diffusion. See the following trac ticket for details. Notice that you can plot this new NetCDF variables and check the distribution of the sponge areas.

[kate]

There is currently no code to write out the 2- or 3-D visc variables. For this sort of check, I would run it in the debugger and query the variables at run time. Others would stick in a print statement.

[wilkin]

One thing to check is analytical.f90 in your Build directory to see if your code was actually activated before compiling.

You do have UV_VIS2 defined, and one of MIX_S_UV or MIX_GEO_UV, right?

[matias.dinapoli]

Hello, my problem was that my model is barotropic, so the flux wasn't affected by a low viscosity. I incremeted the value to 5000 and this worked. I think that more efficient, in my case, is to use nudgings options.

Thanks!

[kate]

If you're trying to damp things out, the model responds well to increasing the bottom drag. Just be sure to turn the limiter on to avoid instabilities.