composition_active_particles.prm

#########################################################
# This is a variation of the composition-active.prm file.
# Here, we track compositional fields and their associated
# density differences with a particle, rather than field,
# based methods.
#
# See the manual for more information about this setup.


set Dimension                              = 2
set Start time                             = 0
set End time                               = 20
set Use years instead of seconds           = false
set Output directory                       = output-composition-active-particles

subsection Geometry model
  set Model name = box

  subsection Box
    set X extent = 2
    set Y extent = 1
  end
end

subsection Boundary temperature model
  set Fixed temperature boundary indicators = bottom, top
  set List of model names = box

  subsection Box
    set Bottom temperature = 1
    set Top temperature    = 0
  end
end

subsection Boundary velocity model
  set Tangential velocity boundary indicators = left, right, bottom
  set Prescribed velocity boundary indicators = top: function

  subsection Function
    set Variable names      = x,z,t
    set Function constants  = pi=3.1415926
    set Function expression = if(x>1+sin(0.5*pi*t), 1, -1); 0
  end
end

subsection Gravity model
  set Model name = vertical
end

subsection Initial temperature model
  set Model name = function

  subsection Function
    set Variable names      = x,z
    set Function expression = (1-z)
  end
end

# Compared to the passive material model, we here make
# the density composition dependent by letting it depend
# linearly on the value of the first compositional field.
subsection Material model
  set Model name = simple

  subsection Simple model
    set Thermal conductivity                           = 1e-6
    set Thermal expansion coefficient                  = 0.01
    set Viscosity                                      = 1
    set Reference density                              = 1
    set Reference temperature                          = 0
    set Density differential for compositional field 1 = 100
  end
end

subsection Mesh refinement
  set Initial adaptive refinement        = 0
  set Initial global refinement          = 5
  set Time steps between mesh refinement = 0
end

subsection Postprocess
  set List of postprocessors = visualization, temperature statistics, composition statistics,particles

  subsection Visualization
    set List of output variables = material properties
    set Time between graphical output = 0.1

    subsection Material properties
      set List of material properties = density
    end
  end

  subsection Particles
    set Time between data output = 0
    set Data output format = vtu
  end
end

# Here, we track compositional fields via active particle particles.
# The initial composition assigned to the particles is 'mapped'
# to the particles at each time step.  This property is accessed in
# the material model through a compositional field (standard method)
# whose values are interpolated from the particles.
subsection Compositional fields
  set Number of fields = 2
  set Names of fields = lower, upper
  set Compositional field methods = particles, particles
  set Mapped particle properties = lower:initial lower, upper:initial upper
end

subsection Initial composition model
  set Model name = function

  subsection Function
    set Variable names      = x,y
    set Function expression = if(y<0.2, 1, 0) ; if(y>0.8, 1, 0)
  end
end

subsection Particles
  set List of particle properties = velocity, initial composition
  set Interpolation scheme = cell average
  set Particle generator name = random uniform

  subsection Generator
    subsection Random uniform
      set Number of particles = 100000
    end
  end
end