The main theoretical assumptions and limitations of linear potential theory employed in Aqwa are listed below:
The body or bodies have zero or very small forward speed.
The fluid is inviscid and incompressible, and the fluid flow is irrotational.
The incident regular wave train is of small amplitude compared to its length (small slope).
The motions are to the first order and hence must be of small amplitude. All body motions are harmonic. The linearized drag damping on the Morison elements (see Morison Drag Linearization) or any additional user-defined viscous damping can be optionally included in the equation of motion.