Flexcom > Theory > Model Building > Vessels and Vessel Motions > RAO Conversions

The conventions used in ANSYS Aqwa are as follows:

•The definition of wave heading is transformed such that a 0 degree heading, which is incident on the stern in the AQWA format, is incident on the bow in the Flexcom format.

•The order of translational RAOs must be changed from AQWA format (Surge, Sway, Heave) to Flexcom format (Heave, Surge, Sway).

•The order of rotational RAOs must be changed from AQWA format (Roll, Pitch, Yaw) to Flexcom format (Yaw, Roll, Pitch).

•The reference units of the rotational RAOs (i.e. whether the angle is specified per metre or per foot) may be adjusted if the AQWA units differ from the Flexcom units. Typically the AQWA units are ascertained automatically from the external file, but as this is not always possible, you are advised to explicitly state the unit system (along with the file name) in order to avoid any possible ambiguity.