Numerical simulation of a helicopter ditching with emergency flotation devices

Smoothed Particle Hydrodynamics (SPH) is used to model the ditching of a helicopter. Helicopters have a high centre of gravity, are not integrally watertight so tend to roll over and sink within seconds of landing on the water surface. Modern helicopters employ Emergency Flotation Systems (EFS) that are essentially large air-bags to provide increased buoyancy and stability to the helicopter, thereby enhancing occupant survival rates. A hybridised finite element code that includes SPH elements, rigid finite elements, flexible finite elements, sliding content interface algorithms and air-bag simulation tools from the automotive industry is used to demonstrate the behaviour of the complex fluid-structure interactions scenario of a helicopter landing on water with and without inflating air-bags.