Floating attitude and floating stability of individual flotation device for aircrews

YONG Wei; DU Haibo; LI Bo; GUO Lei; SONG Xinjun; ZHANG Mingliang; JiANG Lang; XUE Bingjie; LI Falin

doi:10.3969/j.issn.2097-1753.2023.06.002

Abstract：Objective To investigate the floating attitude and floating stability of an individual flotation device in stormy sea environments,and to provide data for structure optimization.Methods A multi-degree-of-freedom motion simulation calculation method was established to analyze the moving posture of the flotation device under the upper limit of class 5 sea state based on overlapping grids.The calculation was based on the unsteady Reynolds-Averaged Navier-Stokes equations,and the VOF multi-phase flow model and turbulence model were introduced.Results In the free-floating state,the device was mainly affected by transverse waves and capsized laterally.The sunken bottom,additional balancing water bags at the bottom edge and additional air bags attached to the flotation device could effectively improve the anti-roll ability of the device under the impact of transverse waves.Moreover,the angle of deflection decreased with the increase of water bags,and a larger size of the additional air bags could do more to restrain the side overturn angle of the device.Conclusion CFD numerical simulation can be used feasibly to study the floating attitude and stability of the flotation device.The overall flotation stability of the device can be effectively improved by reducing height difference of thecenterof gravity and the center of buoyancy after manned operation,increasing rotational inertia of the device around the vertical axis,increasing the recovery moment while the device's overturning tendency occurs and by increasing its anti-overturning moment.