GfsAdaptFunction

From Gerris

GfsAdaptFunction uses a "cell cost" defined by a GfsFunction.

The syntax in parameter files is:

[ GfsAdapt ] [ GfsFunction ]

For example, the following will result in a fine mesh being used only along the interface defined by variable T:

VariableTracerVOF T
...
AdaptFunction { istep = 1 } { cmax = 0 minlevel = 5 maxlevel = 8 } (T > 0 && T < 1)

Examples

• Collapse of a column of grains

    AdaptFunction { istep = 1 } {
	cmax = 0
	maxlevel = LEVEL
    } T

• Viscous folding of a fluid interface

    AdaptFunction { istep = 1 } {
	cmax = 0
	minlevel = min_level
	maxlevel = max_level 
    } (T > 0 && T < 1)

• Savart--Plateau--Rayleigh instability of a water column

    AdaptFunction { istart = 5 istep = 10 } {
	cmax = 0.2
	maxlevel = 10
	cfactor = 2
    } (T > 0 && T < 1 ? dL*Kmax : 0)

• Atomisation of a pulsed liquid jet

    AdaptFunction { istep = 1 } {
	minlevel = 0
	maxlevel = level 
    } (T > 0 && T < 1)

• Air-water flow around a Series 60 cargo ship

    AdaptFunction { istep = 1 } {
        cmax = 1e-2
        # Faster coarsening than with the default cfactor of 4 reduces
        # the size of the simulation
#        cfactor = 2
        # Coarse 'sponge' for x >= 1.5
        maxlevel = (x < 1.5 ? LEVEL : 4)
        minlevel = 4
    } {
        return (T > 0.)*fabs (Vorticity)*ftt_cell_size (cell)/FROUDE;
    }

• Time-reversed advection with curvature-based refinement

    AdaptFunction { istep = 1 } {
    	cmax = 0.1 maxlevel = 8
    	cfactor = 2. 
    } (T > 0. && T < 1.)*dL*fabs(K)

• Viscous flow past a sphere

    AdaptFunction { istep = 1 } { cmax = 1e-2 maxlevel = LEVEL } {
	return (fabs(dx("U"))+fabs(dy("U")))/fabs(U)*ftt_cell_size (cell);
    }

• Shape oscillation of an inviscid droplet

    AdaptFunction { istep = 1 } {
        cmax = 0.01
        maxlevel = LEVEL
    } (T > 0 && T < 1 ? 1. : fabs (Vorticity)*dL)

• Scalings for Plateau--Rayleigh pinchoff

   AdaptFunction { istep = 1 } { 
       # adapt down to 14 levels to capture breakup asymptotics and
       # only 10 levels after breakup
       maxlevel = (t < 0.7455 ? 14 : 10)
       cmax = 0.2 
   } (T > 0 && T < 1)*Kmax*dL

• Sessile drop

    AdaptFunction { istep = 1 } { cmax = 0 maxlevel = LEVEL } (T > 0 && T < 1)