飞行进近中尾流的大涡数值模拟

Large Eddy Simulation of Wake Vortex During Approach

尾流间隔是增大跑道容量的主要限制因素之一,为了在保持安全水平的前提下有效地增大跑道容量,应制定安全高效的尾流间隔。对尾流流场和尾涡消散物理过程的研究,是制定准确、恰当的空中交通中尾流间隔的重要理论依据。本文用大涡模拟方法对三维机翼简化模型的尾流场进行了数值模拟。数值模拟的来流速度、迎角和定解条件等重要参数以航空器尾流事故高发的进近阶段为依据,计算结果验证了涡核的迸裂消散、涡对的连接消散和涡对的下沉现象,发现了在涡对卷起之前的不对称性和Crow关联发生后涡对消散的不对称性,并分析了其原因。

The wake vortex separation is one of the main limitations of the runway capacity increment. To augment the runway capacity while maintaining safety, the wake vortex separation must be regulated based on the consideration of both the safety and the operation efficiency. It is necessary to research the physical process and the dissipation of the wake turbulence to regulate the correct and appropriate wake vortex separation of the air traffic. In this paper, the wake turbulence of a simplified three-dimensional wing model is calculated by a computational fluid dynamics method. The turbulence model is built based on the large eddy simulation theory. The important parameters, such as inlet air velocity, attack angle, and boundary value conditions are in agreement with the data collected from the approach segment of a flight. The given approach segment is the most dangerous segment as far as the wake turbulence is concerned. Numerical simulation results validate the split dissipation of wake vortex core, and the phenomenon of linkage dissipation and sinkage of vortex pair. The dissipation asymmetry of the vortex pair, before roll-up and after the Crow linkage, is discovered. And the reason of the asymmetrical phenomenon is also analyzed.