Boundary conditions

Each boundary has exactly one type of boundary conditions. For periodic boundary conditions, the opposite boundary must also be periodic. The available boundary conditions are given below.

IncompressibleNavierStokes.PeriodicBC — Type

PeriodicBC()

Periodic boundary conditions. Must be periodic on both sides.

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IncompressibleNavierStokes.DirichletBC — Type

DirichletBC()

No slip boundary conditions, where all velocity components are zero.

DirichletBC(u, dudt)

Dirichlet boundary conditions for the velocity, where u[1] = (x..., t) -> u1_BC up to u[d] = (x..., t) -> ud_BC, where d is the dimension.

To make the pressure the same order as velocity, also provide dudt.

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IncompressibleNavierStokes.SymmetricBC — Type

SymmetricBC()

Symmetric boundary conditions. The parallel velocity and pressure is the same at each side of the boundary. The normal velocity is zero.

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IncompressibleNavierStokes.PressureBC — Type

PressureBC()

Pressure boundary conditions. The pressure is prescribed on the boundary (usually an "outlet"). The velocity has zero Neumann conditions.

Note: Currently, the pressure is prescribed with the constant value of zero on the entire boundary.

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IncompressibleNavierStokes.offset_p — Function

offset_p(bc)

Number of non-DOF pressure components at boundary.

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IncompressibleNavierStokes.offset_u — Function

offset_u(bc, isnormal, isright)

Number of non-DOF velocity components at boundary. If isnormal, then the velocity is normal to the boundary, else parallel. If isright, it is at the end/right/rear/top boundary, otherwise beginning.

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