This example clearly illustrated a simple application of sfepy with Navier Stokes problem.

http://sfepy.org/doc-devel/examples/navier_stokes/navier_stokes.html

The inlet/outlet definition:

region_1 = {
    'name' : 'Inlet',
    'select' : 'vertices by cinc0', # In
    'kind' : 'facet',
}
region_2 = {
    'name' : 'Outlet',
    'select' : 'vertices by cinc1', # Out
    'kind' : 'facet',
}

ebc_1 = {
    'name' : 'Walls',
    'region' : 'Walls',
    'dofs' : {'u.all' : 0.0},
}
ebc_2 = {
    'name' : 'Inlet',
    'region' : 'Inlet',
    'dofs' : {'u.1' : 1.0, 'u.[0,2]' : 0.0},
}

This only allows the velocity inlet normal to y axis. If I have an inlet plane that is arbitrary, let say with normal fluid inlet velocity (ux,uy,uz), how should I define the inlet boundary condition?

Moreover, is there any documentation to help me understanding following functions? the syntax is quite different from the typical python one.

functions = {
    'cinc0' : (lambda coors, domain=None: cinc(coors, 0),),
    'cinc1' : (lambda coors, domain=None: cinc(coors, 1),),
}