PUBLIC INTERFACE ~ PUBLIC ROUTINES ~ NAMELIST

Module ocean_lapcst_friction_mod

Contact: 
Reviewers:  Stephen M. Griffies
Change History: WebCVS Log

OVERVIEW

This module computes the thickness weighted and density weighted acceleration for horizontal velocity arising from horizontal Laplacian friction.

This module computes the thickness weighted and density weighted time tendency for horizontal velocity arising from horizontal Laplacian friction. The viscosity used to determine the strength of the tendency can be a general function of space yet it is constant in time. A namelist option exists that determines this viscosity as a local function of the grid spacing.

OTHER MODULES USED

       constants_mod
    diag_manager_mod
             fms_mod
     mpp_domains_mod
             mpp_mod
   ocean_domains_mod
       ocean_obc_mod
 ocean_operators_mod
ocean_parameters_mod
     ocean_types_mod
      ocean_util_mod
 ocean_workspace_mod

PUBLIC INTERFACE

ocean_lapcst_friction_init:
lapcst_friction:
lapcst_viscosity_check:
lapcst_reynolds_check:

PUBLIC ROUTINES

  1. ocean_lapcst_friction_init

    DESCRIPTION
    Initialize the horizontal Laplacian friction module by registering fields for diagnostic output and performing some numerical checks to see that viscosity is set appropriately.


  2. lapcst_friction

    DESCRIPTION
    This routine computes the rho*thickness weighted time tendency for horizontal velocity from horizontal Laplacian friction.


  3. lapcst_viscosity_check

    DESCRIPTION
    Perform linear stability check for the Laplacian operator given a value for the horizontal laplacian viscosity.


  4. lapcst_reynolds_check

    DESCRIPTION
    Subroutine to compute the Laplacian grid Reynolds number. Large Reynolds numbers indicate regions where solution may experience some grid noise due to lack of enough horizontal friction.


NAMELIST

&ocean_lapcst_friction_nml

use_this_module
Must be true to use this module. Default is false.
[logical]
debug_this_module
For debugging by printing checksums.
[logical]
alap
This is the value for the space-time constant Laplacian viscosity.
[real, units: m^2/sec]
velocity_mix_micom
If .true., then the viscosity is set according to a velocity scale times the cube of the grid spacing. It is based on an approach recommended by Eric Chassignet that is used in the Miami Isopycnal Model.
[logical]
vel_micom
Velocity scale that is used for computing the MICOM viscosity.
[real, units: m/sec]

REFERENCES

  1. R. J. Murray and C. J. C. Reason, A curvilinear version of the Bryan-Cox ocean model Journal of Computational Physics (2002), vol 171, pages 1--46
  2. S.M. Griffies, Elements of MOM (2012)

NOTES

The numerical implementation requires no calls to mpp_update_domains.

This scheme has been found to be faster than the Smagorinsky viscosity scheme. However, the algorithm here is less robust since it contains null modes in the terms associated with the sphericity of the earth. Hence, there may be flow configurations that are not dissipated.

The sink from drag next to partial cells has been dropped from MOM4p1.

top