dissipation

The parameter dissipation controls which type of artifical dissipation to apply during a simulation:

dissipation = 0 [Default] No artificial dissipation
dissipation = 1 Diffusion dissipation
dissipation = 2 Kreiss--Oliger dissipation

The dissipation operators are consistent with the summation by parts operators. Consequently, dissipation is applied when deriv_order = 2.
Other parameters associated with artificial dissipation:

sigma_diss [Default] 0.0 . This is the coefficient controlling the size of the dissipation applied. Typically this value is small, around 0.03.
diss_afterinj This parameter is deprecated.

In many applications, artificial dissipation should not be applied to all variables. For those ufuncs to which artificial dissipation should not be applied, the key diss = 0 should be specified in the setup file behind the variable declaration. Example from setup file:
          ufuncs
          {
               D[diss=0], T[diss=0], P
          }
In this example, ufuncs D and T are defined so that no artificial dissipation will ever be applied to them, regardless of the value of the parameters dissipation and sigma_diss. On the other hand, artificial dissipation can be applied to ufunc P.

Notes

Dissipation operations are defined in "had/src/hyperdissipation.f90".

Examples

None

dissipation

Notes

See Also

Examples