GfsSurfaceBc

From Gerris

GfsSurfaceBc is used to set boundary conditions for diffusion equations on embedded solid boundaries.

The syntax in parameter files is:

GfsSurfaceBc V TYPE VAL

where V is a variable name, TYPE is a GfsFunction returning either Dirichlet or Neumann and VAL is a GfsFunction giving the value of the boundary condition.

Examples

• Vortex street around a "heated" cylinder

  SurfaceBc T Dirichlet 1

• Boussinesq flow generated by a heated cylinder

  SurfaceBc T Dirichlet 1

• Creeping Couette flow of Generalised Newtonian fluids

  GfsSurfaceBc U Dirichlet (x*x + y*y > 0.140625 ? 0. : - ay)

  GfsSurfaceBc V Dirichlet (x*x + y*y > 0.140625 ? 0. :   ax)

• Translation of an hexagon in a uniform flow

  SurfaceBc U Dirichlet 1.

• B\'enard--von K\'arm\'an vortex street behind a cylinder translating in a fluid at rest

  SurfaceBc U Dirichlet -1.