This block is used to associate the faces of the cells on the boundary with appropriate boundary conditions.
Element_Number Face_Number Boundary_Name
Element_Number is a positive integer used to identify the element/cell. This is assigned in the ELEMENT block. Face_Number is the face number (0 to 5) that defines the element face. Boundary_Name is the user specified character string used to define the boundary. The Boundary_Name must be unique for each boundary and is defined in BOUNDARY block.