In the unidirectional diffuser, all ports (or nozzles) point to one side of the diffuser line and are oriented
more or less normally to the diffuser line and more or less horizontally.
A unidirectional multiport diffuser hence imparts a net horizontal momemtum flux to the effluent discharge in a direction that is perpendicular to the diffuser main line.
Definition sketches and CorSpy visualizations show these types of duffusers with fanning and without fanning.
The special case where all ports point directly to the water surface should be modeled within CORMIX2 as an alternating diffuser design as it imparts no net horizontal momentum flux to the effluent flow.
Please click on the slide images below to view CorSpy visualizations of various unidirectional multiport diffuser configrations.