Three model-motions were developed to replicate the aerodynamic response of a transverse gust. These motions included a pure-plunging and two three degree-of-freedom motions that approximated the angle-of-attack distribution produced by the gust. Using inviscid models and viscous flow simulations, the response of the gust and model-motions were compared as a function of the non-dimensional reduced frequency. The inviscid model was found to overestimate the influence of the rotational added-mass in the three degree-of-freedom motions. In contrast, the viscous flow simulations showed that the two primary sources of discrepancy between the gust and model-motions lie in the non-linear angle-of-attack distribution caused