Nonlinear air dynamics of a surface effect ship in small-amplitude waves

In many existing works, the seakeeping motions and air dynamics of a surface effect ship (SES) were assumed to be linear under small-amplitude waves (wave amplitude to wave length ratio ≤ 5%) to enhance the computational efficiency. However, according to SES model test results, it was found that even in small-amplitude waves, the fluctuating air cushion pressure shows significantly nonlinear effects. To precisely reveal this distinctive feature, the origin of nonlinearity was carefully investigated and the air leakage was considered as the main source of nonlinearity based on mathematical analysis in this paper. The reason is that the variance of clearance height under seals is comparable t…