Features of vortex trace propagation for aircraft with propellers

The article presents the results of a study of the characteristics of the wake vortex of aircraft with turboprop engines. Using the example of the An-12 aircraft, it is shown that rotating propellers make a noticeable contribution to the propagation of the vortex trail behind the aircraft. This is proved by some studies, as well as numerous observations. It also describes a technique for studying the wake vortex of aircraft with propellers. The method is based on the method of discrete vortices. The relevance of such studies is due to the growing interest of carrier companies in aircraft with turboprop engines. It has been proven that when transporting passengers and cargo on such vessels over distances of 700–800 km, maintenance and fuel costs are reduced by about 30–40%. Therefore, the fleet of turboprop aircraft, such as An-22, An-70, An-12, as well as Tu-95, Il-38, C-130, etc., has been preserved so far. New turboprop aircraft are being developed and put into operation: A-400M, Il-114, Il-112M. The vortex trail behind such aircraft also poses a danger to other aircraft flying behind. A feature of the propagation of the wake vortex behind aircraft with propellers is the interaction of vortices coming off the airframe and vortices from the propellers. As a result, due to the rotation of all the screws in one direction, symmetry is broken in the propagation of vortices descending from the right and left halves of the wing. Therefore, it is important to understand how differently the vortices that descend from the airframe of an aircraft with turboprop engines behave. For the convenience of the study, the method of accounting for the effect of vortices from screws is integrated into a special calculation and software package, also based on the method of discrete vortices. In it, when calculating the characteristics of the wake vortex, the flight weight, speed and altitude of the aircraft, its flight configuration, atmospheric conditions, proximity of the earth, axial velocity in the core of the vortex and some other factors are taken into account. This complex has passed the necessary testing and state registration. A number of measures were carried out to validate and verify the developed complex, confirming the operability of the programs included in it and the reliability of the results obtained from it. The results of the study of the characteristics of the wake vortex behind the Antonov-12 aircraft in the form of vertical velocity spectra and fields of perturbed velocities at various distances from it are presented. It is shown that propellers noticeably affect the propagation of the wake vortex behind turboprop aircraft. This circumstance must be taken into account by the crews of aircraft flying behind such aircraft.

1. Golovnev, I.G., Lapshin, K.V. (2017). On-board air data measurement system as a basis for alerting an aircraft about its entry into a vortex formation from another aircraft. Navigatsiya, navedeniye i upravleniye letatelnymi apparatami: sbornik tezisov dokladov tretyey Vserossiyskoy nauchno-tekhnicheskoy konferentsii. Moscow: Nauchtekhlitizdat, pp. 219–220. (in Russian)

2. Vyshinsky, V.V., Sudakov, G.G. (2009). The vortex track of the aircraft and flight safety issues. Trudy MFTI, vol. 1, no. 3, pp. 73–93. (in Russian)

3. Animitsa, O.V., Gaifullin, A.M., Ryzhov, A.A., Sviridenko, Yu.N. (2015). Simulation of in-flight aircraft refueling on a pilot stand. Trudy MFTI, vol. 7, no. 1, pp. 3–15. (in Russian)

4. Bosnyakov, I.S., Sudakov, G.G. (2013). Modeling the destruction of a vortex wake behind a passenger aircraft using computational aerodynamics methods. Trudy TsAGI, issue 2730, pp. 3–12. (in Russian)

5. Bosnyakov, I.S., Sudakov, G.G. (2014). Calculation of the destruction of the vortex wake behind a passenger aircraft using the method of modeling large vortices of the second order of approximation. Trudy MFTI, vol. 6, no. 3 (23), pp. 3–12. (in Russian)

6. Khaustov, A.A. (2012). Aircraft wake vortex evolution model during cruise. Nauchnyy Vestnik MGTU GA, no. 184, pp. 118–122. (in Russian)

7. Unterstrasser, S., Stephan, A. (2020). Far field wake vortex evolution of two aircraft formation flight and implications on young contrails. The Aeronautical Journal, vol. 124, issue 1275, pp. 667–702. DOI: 10.1017/aer.2020.3

8. Speijker, L., Vidal, A., Barbaresco, F., Frech, M., Barny, H., Winckelmans, G. (2007). ATC-Wake: Integrated wake vortex safety and capacity system. Journal Air Traffic Control, vol. 49, no. 1, pp. 17–32.

9. Gillis, T., Marichal, I., Winkelmans, G., Chatelain, F. (2019). A 2D immersed interface Vortex Particle-Mesh method. Journal of Computational Physics, vol. 394, pp. 700–718. DOI: 10.1016/j.jcp.2019.05.033

10. Stephan, A., Schrall, J., Holzäpfel, F. (2017). Numerical optimization of plate-line design for enhanced wake-vortex decay. Journal Aircraft, vol. 54, no. 3, pp. 995–1010. DOI: 10.2514/1.C033973

11. Stephan, A., Rohlmann, D., Holzäpfel, F., Rudnik, R. (2019). Effects of detailed geometry on aircraft wake vortex dynamics during landing. Journal of Aircraft, vol. 56, no. 3, pp. 974–989. DOI: 10.2514/1.C034961

12. Ginevsky, A.S., Zhelannikov, A.I. (2009). Vortex traces of aircraft. Springer Berlin, Heidel-berg, 154 p. DOI: 10.1007/978-3-642-01760-5

13. Gulyaev, V.V., Zhelannikov, A.I., Moroshkin, D.V., Ushakov, S.A. (2007). The mathematical model of a distant vortical trace behind the airliners with propellers. Nauchnyy Vestnik MGTU GA, no. 111, pp. 21–27. (in Russian)

14. Zhelannikov, A.I., Zamyatin, A.N. (2015). The certificate of state registration of program for computer № 2015614783 "Design-a software package for the system of vortex-Reva security".

15. Belotserkovsky, S.M., Nisht, M.I. (1978). Separation and non-separation flow of thin wings with an ideal liquid. Moscow: Nauka, 277 p. (in Russian)

16. Aparinov, V.A., Dvorak, A.V. (1986). The method of discrete vortices with closed vortex frames. Trudy VVIA im. Prof. N.E. Zhukovskogo, issue 1313, pp. 424–432. (in Russian)

17. Setukha, A.V. (2020). Lagrangian description of three-dimensional viscous flows at large Reynolds numbers. Computational Mathematics and Mathematical Physics, vol. 60, no. 2, pp. 302–326. DOI: 10.1134/S0965542520020116

18. Belotserkovsky, S.M., Ginevsky, A.S. (1995). Modeling of turbulent jets and traces based on the discrete vortex method. Moscow: Fizmatlit, 368 p. (in Russian)

19. Barnes, C.J., Visbal, M.R., Huang, P.G. (2016). On the effects of vertical offset and core structure in stream wise oriented vortexwing interactions. Journal of Fluid Mechanics, vol. 799, pp. 128–158. DOI: 10.1017/jfm.2016.320

20. McKenna, C., Bross, M., Rockwell, D. (2017). Structure of a stream wise oriented vortex incident upon a wing. Journal of Fluid Mechanics, vol. 816, pp. 306–330. DOI: 10.1017/jfm.2017.87

21. Winckelmans, G., Cottin, C., Daeninck, G., Leweke, T. (2007). Experimental and numerical study of counter-rotating vortex pair dynamics in ground defect. In: 18th Congress Français de Mécanique, pp. 28–33.

22. Winckelmans, G., Bricteux, L., Cocle, R., Duponcheel, M., Georges, L. (2007). Assessment of multiscale models for LES: spectral behavior in very high Reynolds number turbulence and cases with aircraft wakes vortices. In: Proceeding 5th International Symposium on Turbulence and Shear Flow Phenomena (TSFP-5), Garching, Germany, vol. 1, pp. 327–331.

23. Frech, M., Holzapfel, F. (2008). Skill of an aircraft wake-vortex model using weather prediction and observation. Journal of Aircraft, vol. 45, no. 2, pp. 461–470. DOI: 10.2514/1.28983

24. Holzapfel, F., Steen, M. (2007). Aircraft Wake-Vortex Evolution in Ground Proximity: Analysis and parameterization. Aeronautics I Astronautics Journal, vol. 45, no. 1, pp. 218–227. DOI: 10.2514/1.23917

25. Vyshinsky, V.V., Sudakov, G.G. (2006). Vortex trace of an airplane in a turbulent atmosphere. Trudy TsAGI, issue 2667, 155 p. (in Russian)

26. Grigorev, M.A., Zamyatin, A.N., Rogozin, V. (2016). Airflow visualization during research of large scale vortex flows. In: ICAS 2016, 30th Congress of the International Council of the Aeronautical Science in Daejeon. Korea, pp. 1–7.

27. Grigorev, M.A., Zamyatin, A.N. (2016). Experimental and theoretical investigations of large scale vortex flows. In: ICVFM 2016, 7th International Conference on Vortex Flows and Vortex Models. Rostock, Germany, pp. 98–99.