Research On Dynamic Reduction Technology Of Wake Separation For Approaching Aircraft

In recent years,China has been completing the transition from a civil aviation power to a strong civil aviation power.The increasing air traffic flow brought about by the rapid development of China’s civil aviation has deepened the contradiction between the growing air traffic flow and limited airspace resources.In order to improve control efficiency and reduce flight delays,it is necessary to optimize the existing conservative wake separation standards.Based on ADS-B data,this thesis analyzed the changing characteristics of aircraft flight speed during approaching,and researched the characteristics of aircraft wake evolution,follower response,and wake encounter risk with speed change.Finally,a complete dynamic wake separation reduction research method based on speed change was proposed.The main work of the thesis includes:Firstly,based on the ADS-B data of aircraft at Shanghai Pudong Airport,the change characteristics of aircraft speed during the approach phase were analyzed.The characteristic parameters and induced speed of wake vortex generated by typical aircrafts under different approach speeds were calculated,and the change law of wake vortex generation characteristics with approach speed was analyzed.The dissipation parameters of wake vortex generated by typical aircrafts under different approach speeds were calculated,and the change law of wake vortex dissipation characteristics with approach speed was analyzed.Taking into account the influence of approach speed changes on wake vortex generation and dissipation,the evolution law of wake vortex under different approach speeds was obtained.Secondly,the main types and hazards of wake encounter during approaching phase are analyzed,and a wake encounter response model based on aircraft aerodynamic characteristics is established.For typical aircrafts with different engine layouts,calculated the lift change and roll moment induced by the wake of the preceding aircraft when the following aircraft flies with the existing wake separation standard at different approach speeds,and analyzed their change laws with the approach speed.Then,starting from the two attitude changes of roll and pitch that may occur when the aircraft encounters wake turbulence,analyzed the safety indicators that can be used to quantify the risk of aircraft wake encounter,and selected roll moment coefficient and bump intensity to evaluate wake encounter risk.Combining the wake evolution and wake encounter response models,evaluated the risk of encountering wake turbulence when implementing the existing wake separation standards at different approach speeds for typical aircrafts,and judged the potential for reducing the existing wake separation standards.Finally,based on the aircraft wake encounter response model and roll moment coefficient,constructed a simplified hazard area(SHA)for wake turbulence,and analyzed the changes in lateral and vertical safety separation for typical aircraft combinations.Using the roll moment coefficient limit value as the safety criterion,calculated the minimum longitudinal safety separation for typical aircraft combinations at different approach speeds.Based on the approach speed changes of typical aircrafts in the ideal approaching phase,the minimum safety separation was dynamically calculated and the dynamic reduction simulation of wake separation was completed.This research proved the safety of the existing wake separation standard,and proposed a dynamic separation reduction method to improve the operation efficiency of airports and airspace,which can provide theoretical reference for optimizing the existing wake separation standard and air traffic control operation mode.