The phase angle defines the time difference between an oscillatory parameter and a reference point. In Aqwa, the reference point for the phase angle of a parameter is the zero phase angle of the incident wave, which corresponds to the time when the wave crest is at the CoG of the structure. In the Aqwa-Line output file, most calculated parameters are given in the form of an amplitude and a phase angle. A positive phase angle indicates that a parameter reaches its peak value after the wave crest has passed the CoG of the structure, and the time difference is decided by:

where:

= wave period

= phase (degrees)