RELAX {COUPLE | COUPLING} factor \
   [ZONE range1[,range2[, ... rangen]] \
    [[BOUNDARY] {ALL | I1 | IMAX | J1 | JMAX | K1 | KMAX}]]

This keyword allows the user to specify the relaxation factor when using characteristic zone coupling. factor may range from 0.0 for no coupling, to 1.0 for full zone coupling. In the zone specification, the range parameter(s) must be one of the following forms:

	zonenum		Selects zone zonenum
	begzone:endzone		Selects all zones from begzone to endzone
	begzone:		Selects all zones from begzone to MAXZONE, the total number of zones in the grid file
	:endzone		Selects all zones from 1 to endzone
	ALL		Selects all zones

If the zone specification is omitted, the specified factor will be applied at all boundaries in all zones. Note that a boundary cannot be specified without the zone specification.

If a zone (or zones) is specified, but the boundary is not (or the boundary is specified as BOUNDARY ALL), the specified factor will be applied at all boundaries in the specified zone(s).

The default relaxation factor is 0.7 for steady-state calculations, and 1.0 for for space-marching and time-accurate calculations. If the RELAX COUPLING keyword is used, and all zones are selected (either by omitting the zone specification, or by specifying ZONE ALL), the relaxation factor is automatically set to 1.0 for space-marching and time-accurate calculations. However, if specific zones were selected, the specified factor will be used at the specified boundary in those zones, even for space-marching and time-accurate calculations.