However, when obtaining the details of the flow field, the accuracy of the simplified vortex model is worse than that of a real case or numerical simulations. ![]() There is also a significant gap between wind tunnel tests and actual airport approach. Due to the existence of the wind tunnel wall and the limitation of the length of the effective test section, wind tunnel experiments cannot meet the research requirements of long-distance wake vortex development. Although airport measurements provide first-hand data, the complex atmospheric environment and measuring equipment with a finite resolution limit the observation accuracy. Outfield observations, wind tunnel experiments, simplified vortex models of the wake flow, and numerical simulations are the primary research methods for the evolution of vortices. Therefore, we chose to study a model without considering flutter behaviors in our present research. However, the flutter would cause small movements of the wing relative the scale of the entire airplane. The wingtip would suffer from unstable flow conditions during the flight. ( Citation2019) studied the flutter behavior of a typical wing. ![]() ( Citation2020) studied the influence of powered nacelles in maintaining the separation vortex. Several methodological aspects of data evaluation and interpretation have been recommended, along with vortex encounter models and wake–vortex safety assessment. ( Citation2002) discussed the problem of commercial aircraft wake vortices. Proctor and Switzer ( Citation2000) discovered the dissipation behaviors of wakes using the large eddy simulation method (Ghias et al., Citation2004 Han et al., Citation2000), which is an accurate, complex, and inefficient method. In addition, he also described the vortex dissipation through a further experimental study based on the eddy dissipation rate instead of the turbulent kinetic energy. Sarpkaya ( Citation2000) created a new model for vortex decay in the far field. Crow and Bate ( Citation1976) concluded that the turbulent atmosphere would excite the mutual induction instability that shorten the typical lifespan of a Boeing 747 wake. Crow ( Citation1970) made numerous observations and proposed the Crow instability based on the formation and dissipation characteristics of the wake vortices. ![]() The simulation of the wake vortex flow field is a significant basis of analysis for airport safety intervals. The influence of the wake vortex may last for several minutes according to the existing civil aviation security standards. Meanwhile, excessive vortex spacing will waste airport runway resources (Perry et al., Citation1997) (Hallock & Holzäpfel, Citation2018). The wake decay near the ground will have adverse effects on the flight safety for the following aircraft. Although the current take off and approaching interval standard (ICAO, Citation2016) avoids wake vortex hazards, the airport capacity under certain circumstances is severely limited. A following aircraft may suffer from tilt, roll, stall, sharp pitch, and other dangerous situations that affect flight safety under the influence of downwash when entering the wake region of a leading aircraft. There are many factors that affect wake vortex decay mechanisms, such as atmospheric turbulence, the airport ground, crosswinds, and the mutual induction of vortex systems. What influences the airport efficiency most is the wake flow generated by aircraft wings. Thus, improving the efficiency of take off and landing at airports under safe conditions has become a key issue in civil aviation. Aircraft play an important role in transportation.
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