Assigning Opening Properties

An opening is a two-dimensional modeling boundary condition that represents an area on the surface of a solid object (such as a block or plate) or an area on a planar object such as a wall through which a fluid is free to flow in any direction. Opening types include free and recirculating. Free openings are specified individually, and recirculating openings must be specified in pairs. Recirculating opening pairs consist of two sections:

• an extract section, representing the location at which fluid is removed from the enclosure
• a supply section, representing the location at which fluid is returned to the enclosure

Openings should be located on an enclosure boundary, that is, either a mesh region wall or the surface of a hollow block that has been used to mask a portion of the enclosure. Free openings can be located on the surfaces of blocks or plates within the enclosure.