Aircraft tire-water film-pavement interaction on wet pavement in landing

Based on hydrodynamic equilibrium equations of aircraft tire-water film-wet pavement interaction during the aircraft landing on the wet pavement, main influence factors of hydrodynamic pressures in tire-water film interaction were obtained. They are water film thickness, aircraft's taxiing speed and tire tread depth. On the basis of this result, three-dimensional solid model of tire-water film-pavement was established, in which the main tire of Boeing 737-800 was taken as the research object here. Then the finite element analysis model was established based on Fluent software. The water distribution and average hydrodynamic pressures on water attaining surface of the tire were obtained by volume of fluid (VOF) method and three main influence factors of hydrodynamic pressure were analyzed by above finite element model. Some conclusions can be drawn as follows. Water film thickness and taxiing speed of aircraft are two outstanding influence factors of hydrodynamic pressure and the hydrodynamic pressure linearly increases with the increase of water film and aircraft's taxiing speed. The hydrodynamic pressure increases faster at a water film thickness above 3mm, and at the water film thickness of 12 mm, the hydrodynamic pressure reaches and exceeds the tire pressure (1.47 MPa), which leads to hydroplaning of the aircraft's tire.When the taxiing velocity is less than 100 km/h, the hydrodynamic pressure is less than the tire pressure which means no hydroplaning risk for the aircraft. Based on the above analysis results, relational expression between the hydrodynamic pressure and water film thickness, aircraft's taxiing speed and tire tread depth was established. Considering the lift force during landing, the critical hydroplaning speeds and the length increment of landing distance of Boeing 737-800 were obtained under different rainfall conditions to provide important theoretical foundations for landing and safe taxiing of the aircraft.