Radar Simulation of Wake Vortices in Rainy Conditions Based on the Euler-Euler Multiphase Model

Zhou Jin-Xin,Zhang Ze-Yu,Li Dong

doi:10.1109/access.2020.2975052

Zhou Jin-Xin, Zhang Ze-Yu + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.2975052

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Abstract

The radar monitor of aircraft wake vortex is of great significance to air traffic control. Comparing with the case in clear air, the radar signal of wake vortices in rainy conditions is more easily captured due to the higher levels of signal. To able to analyze radar echo characteristics of evolving wake vortices, the numerical simulation of the evolution of the wake vortices in various rain rates has been performed based on the Euler-Euler frame. The result shows that the rainfall can accelerate the decay of wake vortices. A radar simulator has been represented to process the radar echo signal of raindrops around the wake vortex. The Doppler spectrum of echo signals in radar resolution volumes has been analyzed and the straight vortex and the vortex ring phases show different characteristics of spectrum width. The Doppler width information based on this result of interaction between the wake vortex and rain can be used for assessing the decay phase of wake vortices and monitoring potential hazard for wake vortex encounters.

Highlights

Aircraft wake vortex is a by-product of the lift, which is a pair of counter-rotating vortices
To further assess the relationship between the Doppler spectrum width and the wake vortex intensity, the radar simulator is used for the whole vortex age and the results of 5 mm/h and 10mm/h are averaged to reduce the effect of uncertain rain rates
Comparing with the Euler–Lagrange model, the approach takes the effect of raindrops dynamics on the wake vortex evolution into account

Summary

INTRODUCTION

Aircraft wake vortex is a by-product of the lift, which is a pair of counter-rotating vortices. Li et al [10] well estimated velocities and accelerations of the raindrops around wake vortices, proposed a circulation retrieval method based on a vertically pointing radar under the rain condition and verified the retrieval method through numerical simulation results. In these studies, wake vortices were treated as static velocity fields and did not evolve with time. In this simulation, three moderate to low rain rates (the initial volume fraction of rain flow field) are considered: 0mm/h, 5mm/h and 10mm/h, respectively. The numerical time step is fixed as 0.01 s

RADAR SIMULATOR

BASIC STRUCTURE OF THE RADAR SIMULATOR

WEIGHTING FUNCTIONS

CONCLUSION