Information on ocean environmental conditions, such as winds, waves and current, is critical for the design of all types of marine structures, and is especially important for floating offshore structures for which hydrodynamic behavior in open sea is more complicated than fixed structures. Waves apply exciting forces at wave frequency and nonlinear wave forces (for example, low frequency drift force and sum frequency second order forces), or alternatively nonlinear wave forces due to variation of the instantaneous wetted hull surface. Winds and current cause forces on the exposed members of the structure above and below the water surface respectively, and the forces are generally evaluated in Aqwa by a nonlinear drag force term.

This chapter describes the numerical models of waves, wind, and current available in Aqwa.