侧风对直升机沙盲特性的影响

The complex interaction flow between the helicopter rotor and ground induced the movement of sand particles in the sand bed and then yielded helicopter brownout. However, a crosswind will change the rotor-ground interaction flow field, and influence the brownout. Therefore, a crosswind is coupled into the helicopter rotor-ground aerodynamic model based on viscous vortex particles to consider the influence of the crosswind on the rotor-ground interaction flow field. In order to take into account how the crosswind affects sand movement, the air force caused by the crosswind is also incorporated to the sand particle dynamic model based on DEM. Then, the effect of the crosswind on the process of helicopter brownout at forward flight is analyzed, and the influences of velocity, and direction of the crosswind on the brownout are also investigated. Results show that the crosswind has a significant influence on the helicopter brownout, the density of dust cloud obviously increases with the crosswind at the port side, and it is restrained at forward flight. The density of the dust cloud firstly increases and then decreases with increasing the velocity of crosswind at the port side.