Research on slamming load-reduction method for seaplane water landing based on pressure-relievable cavities

This study proposes a pressure-relievable cavity method to mitigate slamming loads during seaplane water landings. The method reduces impact loads by decreasing the forebody wetted area during initial water entry. Validated through prototype-scale numerical simulations and 1:40 scale combined numerical-experimental tests for zero-pitch-angle landing, the approach achieves over 30% load reduction in calm water and over 20% load reduction during landings near the wave crest. Under the following wave conditions, slamming loads are classified into single-peak, primary–secondary-peak, and multi-peak patterns. The effectiveness of full- and single-cavity activation is evaluated across these regimes. While cavity-induced free-surface disturbances may generate new high-pressure zones, potentially diminishing or reversing load reduction, optimal performance is achieved by tailoring cavity activation to the slamming pattern. Full activation is most effective for single-peak and primary–secondary-peak cases, whereas selective activation disrupts high-pressure regions. For the multi-peak case, opening a forward cavity reduces loads by disrupting the forebody high-pressure region and avoiding the aftbody slamming amplification from rear- or full-cavity activation. This work provides a design framework for effective slamming mitigation and enhanced safety in emergency seaplane operations.