Dynamic Characteristics Analysis of the Helicopter-Airbag Wave Landing on Different Positions

A numerical regular wave tank is established based on the multi-material ALE method and plane wavemaker. The wave landing of the helicopter-airbag is numerically studied at different landing position of wave surface respectively, including the peak, trough, half slope of upwind side, and half slope of downwind side. The results show that, the position of water landing has an effect on the maximum pitch angle and the vertical peak impact acceleration of the helicopter. Landing on wave crest leads to the most pitch angle -20.4°, which is most unfavorable for the wave landing stability of the helicopter. The peak vertical acceleration of a helicopter is related to its vertical water impact velocity and water impact angle. Among all the landing positions, the maximum vertical acceleration is 12.82g, which occurs on water landing on half slope of upwind side of wave.