GfsBcNavier is used to impose a Navier slip condition (for velocity or Robin boundary condition for a tracer) of the form
- vboundary = v0 + λ ∂n vboundary
where ∂n is the derivative normal to the boundary and v0 and λ are parameters.
The syntax in parameter files is
[ GfsBc ] V0 LAMBDA
LAMBDA are the parameters. Both
LAMBDA are GfsFunctions.