基于响应面法的短距/垂直起降飞机近地面升力损失

建立了短距/垂直起降(S/VTOL)飞机近地面升力损失的流场计算模型.通过数值模拟得出特定升力布局的飞机近地面状态各工况的升力损失.采用响应面法获得了飞机升力损失关于喷管落压比（NPR）、来流速度及飞机高度的2阶响应曲面函数及显著影响飞机升力损失的关键因素.并分析了喷管落压比、来流速度及飞机高度对飞机升力损失的交互影响作用，优化得出给定工况范围内升力损失最小的工作点.研究表明:仅考虑单因素影响时，升力损失随高度、落压比的增大而减小，随来流速度的增大而增大；考虑两因素交互作用时，高度与落压比及来流速度与落压比对升力损失存在交互影响，而高度与来流速度对升力损失无交互影响；优化获得的升力损失最小的工作点是飞机距地面高度为9D（D为喷管直径）、喷飞机高度为3、来流速度为0m/s，此时的升力损失为1.3%. 

Lift loss of short/vertical takeoff and landing aircraft proximity of ground based on response surface method

The lift loss flow field calculation model of short/vertical takeoff and landing (S/VTOL) aircraft proximity of the ground was built.The two order response surface func tion of lift loss about nozzle pressure ratio (NPR),velocity of the cross wind and height of the plane above ground,as well as the key factors affecting the lift loss significantly at multi working states proximity of the ground were obtained by response surface method.The interaction effect of NPR,velocity of the cross wind and height of the plane above ground on the lift loss was analyzed and the minimum lift loss in certain range of working state was optimized.The study shows that the lift loss reduces with the increasing height of the plane above ground and NPR and increases with the velocity of the cross wind when considering single factor;the interaction effect on the lift loss exists between height of the plane above ground and NPR,velocity of the cross wind and NPR,the interaction effect on the lift loss doesn't exist between height of the plane above ground and velocity of the cross wind,the minimum lift loss obtained by optimization is at height of the plane above ground of 9D (D is nozzle diameter),nozzle pressure ratio of 3,velocity of the cross wind of 0 m/s working state,and the corresponding lift loss is 1.3 ％.