two-phase-levelset.h

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/** @file two-phase-levelset.h
 */
/**
# Two-phase interfacial flows with levelset
 
This file helps setup simulations for flows of two fluids separated by
an interface (i.e. immiscible fluids). It is typically used in
combination with a [Navier--Stokes solver](navier-stokes/centered.h). 
 
The interface between the fluids is tracked with a levelset
method. The signed distance to the interface is tracked by `d`. The
volume fraction field `f` is computed from the signed distance.
 
Note that the [coupled VOF and levelset solver](two-phase-clsvof.h)
should be prefered as it ensures much better mass conservation.
 
This solver can be combined with the [integral formulation of surface
tension](integral.h).
 
The volume fraction in fluid 1 is \f$f=1\f$ and \f$f=0\f$ in fluid
2. The densities and dynamic viscosities for fluid 1 and 2 are *rho1*,
*mu1*, *rho2*, *mu2*, respectively. */
 
#include "tracer.h"
 
scalar d[], f[], * tracers = {d};
 
#include "two-phase-generic.h"
 
void levelset_to_vof (scalar d, scalar f)
{
  scalar phi[];
  for (int _i = 0; _i < _N; _i++) /* foreach_vertex */
    phi[] = (d[] + d[-1] + d[0,-1] + d[-1,-1])/4.;
  fractions (phi, f);
}
 
/**
The initial volume fraction is computed from the initial distance
field, which must be initialised by the user. */
 
/** @brief Event: init (i = 0) */
void event_init (void) 
{
  levelset_to_vof (d, f);
}
 
/**
The distance function is reinitialised at each timestep. */
 
#include "redistance.h"
 
/** @brief Event: properties (i++) */
void event_properties (void) 
{
  redistance (d, imax = 3);
  levelset_to_vof (d, f);
}
 
/**
## See also
 
* [Two-phase interfacial flows with VOF](two-phase.h)
* [Two-phase interfacial flows with coupled levelset and VOF](two-phase-clsvof.h)
*/