## multicomponent

- ex19.c Nonlinear driven cavity with multigrid in 2d.
  The 2D driven cavity problem is solved in a velocity-vorticity formulation.
  The flow can be driven with the lid or with bouyancy or both:
  -lidvelocity <lid>, where <lid> = dimensionless velocity of lid
  -grashof <gr>, where <gr> = dimensionless temperature gradent
  -prandtl <pr>, where <pr> = dimensionless thermal/momentum diffusity ratio
  -contours : draw contour plots of solution
- ex27.c Nonlinear driven cavity with multigrid and pusedo timestepping 2d.
  The 2D driven cavity problem is solved in a velocity-vorticity formulation.
  The flow can be driven with the lid or with bouyancy or both:
  -lidvelocity <lid>, where <lid> = dimensionless velocity of lid
  -grashof <gr>, where <gr> = dimensionless temperature gradent
  -prandtl <pr>, where <pr> = dimensionless thermal/momentum diffusity ratio
  -contours : draw contour plots of solution
- ex29.c Hall MHD with in two dimensions with time stepping and multigrid.
  -options_file ex29.options
  other PETSc options
  -resistivity <eta>
  -viscosity <nu>
  -skin_depth <d_e>
  -larmor_radius <rho_s>
  -contours : draw contour plots of solution
- ex30.c Steady-state 2D subduction flow, pressure and temperature solver.
  \\nThe flow is driven by the subducting slab.
  -ivisc <#> = rheology option.
  0 --- constant viscosity.
  1 --- olivine diffusion creep rheology (T-dependent, newtonian).
  2 --- weak temperature dependent rheology (1200/T, newtonian).
  -ibound <#> = boundary condition
  0 --- isoviscous analytic.
  1 --- stress free.
  2 --- stress is von neumann.
  -icorner <#> = i index of wedge corner point.
  -jcorner <#> = j index of wedge corner point.
  -slab_dip <#> = dip of the subducting slab in DEGREES.
  -back_arc <#> = distance from trench to back-arc in KM.(if unspecified then no back-arc).
  -u_back_arcocity <#> = full spreading rate of back arc as a factor of slab velocity.
  -width <#> = width of domain in KM.
  -depth <#> = depth of domain in KM.
  -lid_depth <#> = depth to the base of the lithosphere in KM.
  -slab_dip <#> = dip of the subducting slab in DEGREES.
  -slab_velocity <#> = velocity of slab in CM/YEAR.
  -slab_age <#> = age of slab in MILLIONS OF YEARS.
  -potentialT <#> = mantle potential temperature in degrees CENTIGRADE.
  -kappa <#> = thermal diffusivity in M^2/SEC.
  -peclet <#> = dimensionless Peclet number (default 111.691)
  \