基于时间间隔标准的尾流安全评估分析方法

Wake safety assessment method based on time separation criteria

科学地优化飞机间尾流间隔是提升机场吞吐量的重要举措,确保安全是尾流间隔实施的首要前提。首先,基于大涡模拟试验数据,对经典的两阶段消散模型(Wake Two-Stage Decay Model,D2P)模型进行改进,创建顶风对尾涡环量衰减的影响模型。然后,针对基于时间间隔(Time-Based Separation,TBS)未考虑顶风会影响尾涡移动和尾涡环量衰减,通过转化为飞机地速和构建改进D2P模型深刻分析两因素对尾涡遭遇严重度的影响。最后,计算实施TBS时不同风速不同机型组合对应的最小尾流间隔,并综合分析对应间隔的尾涡遭遇严重度。结果表明:虽然TBS未考虑顶风对尾涡移动和环量衰减的影响,但可以确保前后机安全性;在顶风8 m/s应用TBS方案时,各机型组合的尾涡遭遇严重度约为静风时的30%。TBS安全地缩减了顶风时的尾流间隔。

Scientific optimization of aircraft wake separation is a significant measure to improve airport capacity,and ensuring safety is the primary prerequisite for the implementation of wake separation.First,the model of the Time-Based Separation(TBS)method was developed.Based on the numerical simulation experimental data,the influence of the headwind on the wake vortex rapid decay onset time was added.The classical Wake Two-Stage Decay Model(D2P)model was improved by fitting the experimental results using MATLAB.By comparing the results of the large eddy simulation experiment and the improved model,the feasibility of improving the model was verified.Then,the induced rolling moment coefficient model was developed and used to calculate the severity of wake vortex encounters.Combined with the influence of headwind on wake vortex,the advantages and disadvantages of TBS method without considering two factors(the influence of headwind on wake vortex movement and decay)on wake separation reduction were analyzed.Finally,the wake safety separation of TBS at different headwinds was calculated.The safety of the TBS method was evaluated by considering the effects of headwinds on the aircraft s ground speed,wake vortex circulation decay,and wake vortex motion.The results show that the influence of accelerating the wake decay of the headwind is greater than the effect of reducing the separation and the wake vortex movement,so the TBS method can ensure the safety of the leading and following aircraft.Even the wake separation can be further reduced,and at 8 m/s the separations of the reducible aircraft combination are reduced by an average of about 7%compared to Re-categorization-China(RECAT CN).When the TBS scheme is implemented at a headwind of 8 m/s,the Rolling Moment Coefficient(RMC)of six groups of different aircraft combinations is about 30%of the clam wind.TBS method eliminates the influence of some headwinds on wake separations,which is conducive to increasing airport capacity.