GfsProjectionParams

From Gerris

Revision as of 23:32, 29 August 2011; view current revision
←Older revision | Newer revision→
Jump to: navigation, search

GfsProjectionParams can be used to tune the Poisson solver (for the MAC projection). Ideally, this should rarely be necessary.

The syntax in parameter files is:

GfsProjectionParams {
   tolerance = 1e-3
   nrelax = 4
   erelax = 1
   minlevel = 0
   nitermax = 100
   nitermin = 1
   omega = 1
   function = 0
}

with

tolerance
the maximum magnitude of the relative change in volume of any cell in one timestep (i.e. the maximum error allowed in local volume/mass conservation).
nrelax
the number of relaxations on the finest level of the multigrid hierarchy.
erelax
the factor by which to multiply the nrelax parameter when going up (i.e. coarser grids) the multigrid hierarchy.
minlevel
the coarsest level to consider in the multigrid hierarchy.
nitermax
the maximum number of iterations of the multigrid before giving up.
nitermin
the minimum number of multigrid iterations.
omega
the over-relaxation parameter.
function
whether to compute the cell-face diffusion coefficients directly from the equation of state (rather than averaging the cell-centered values).

The default values are those given in the syntax description.

Note that GfsApproxProjectionParams should usually be setup to match GfsProjectionParams.

Examples

Personal tools
communication