NUMERICAL INVESTIGATION OF X-45A TYPE UNMANNED COMBAT AIR VEHICLE

Öz

In this paper, the low-speed aerodynamic performance of unmanned combat air vehicle (UCAV) X-45 delta wing was investigated by a numerical method using computational fluid dynamic approaches (CFD). The investigation was conducted with X-45 and the formation of leading-edge vortices (LEV) and vortex breakdown was studied by a varying angle of attack with the range of 5° to 30° at the Reynolds number of 10,000 using the SST turbulence model and are compared with experimental data to validate simulation accuracy of CFD. Stall conditions happened at around 30°, averaged vorticity layer demonstrates a prolonged form that goes along by narrow recirculation zones neighboring to the wing surface. Detail about flow field, including LEV formation, vortex breakdown, interaction, and nonlinear aerodynamic characteristics of X-45 was presented and discussed.

Anahtar Kelimeler

• LEV
• CFD
• delta wing
• X-45

X-45A Tipi İnsansız Muharebe Hava Aracının Nümerik Olarak İncelenmesi

Öz

Bu çalışmada, insansız savaş hava aracı (SİHA) X-45 delta kanadının düşük hızlı aerodinamik performansı hesaplamalı akışkanlar dinamiği yaklaşımları (HAD) kullanılarak sayısal bir yöntemle incelenmiştir. İnceleme X-45 ile yürütülmüş ve öncü girdapların (LEV) oluşumu ve girdap kırılması, SST türbülans modeli kullanılarak Reynolds sayısı 10.000'de 5° ila 30° aralığında değişen bir hücum açısı ile incelenmiştir. CFD'nin simülasyon etkinliğini doğrulamak için daha önceden yapılan deneysel verilerle karşılaştırılmıştır. Stol koşulları yaklaşık 30°'de meydana gelmiş, ortalama girdap katmanı, kanat yüzeyine komşu dar döngüsel bölgeleri boyunca uzanan uzun bir form göstermektedir. LEV oluşumu, girdap bozulması ve etkileşimi ve X-45'in doğrusal olmayan aerodinamik özellikleri dahil olmak üzere akış alanı hakkında ayrıntılar sunulmuş ve tartışılmıştır. 

Anahtar Kelimeler

• LEV
• CFD
• delta kanat
• X-45

Kaynakça

1. 1. Lambourne, N.C., and Bryer, D.W. (1961). The Bursting of Leading-Edge Vortices – Some observations and Discussion of the Phenomenon. ARC R&M 3282.
2. 2. Sarpkaya T. (1971) Vortex breakdown in swirling conical flows. AIAA J:9(9):1792±9.
3. 3. Faler J.H., Leibovich S. (1978) An experimental map of the internal structure of a vortex breakdown. J Fluid Mech;86(2):313±35.
4. 4. Sahin, B., Tasci, M. O., Karasu, I., & Akilli, H. (2017). Flow structures in end-view plane of slender delta wing. In EPJ Web of Conferences (Vol. 143, p. 02099). EDP Sciences.
5. 5. Canpolat C., Yayla S., Sahin B., Akilli, H (2012). “Observation of the Vortical Flow over a Yawed Delta Wing”, Journal of Aerospace Engineering, Vol.25, pp. 613-626.
6. 6. Yaniktepe, Bulent, Coşkun Ozalp, And Cetin Canpolat. (2016) Aerodynamics and Flow Characteristics of X-45 Delta Wing Planform." Kahramanmaras Sutcu Imam University Journal of Engineering Sciences 19.1: 1-10.
7. 7. Swan, Sarah (2006). X-45A Unmanned Combat Vehicle on Display. Aerotech News and Review.
8. 8. Elkhoury, M., Yavuz, M. M. and Rockwell, D., (2005). Near-Surface Topology of a Unmanned Combat Air Vehicles Planform: Reynolds Number Dependence. Journal of Aircraft, Vol. 42, No. 5, pp. 1318-1330.

9. 9. Canpolat C., Yayla, S., Sahin, B., and Akilli, H. (2009). Dye Visualization of the Flow Structure over a Yawed Nonslender Delta Wing, Journal of Aircraft ,Vol. 46, No. 5.
10. 10. Yaniktepe, B., and Rockwell, D. (2004). Flow Structure on a Delta Wing of Low Sweep Angle AIAA Journal, Vol. 42, No. 3.
11. 11. F.R. Menter, (1994) Two-Equation Eddy-Viscosity Turbulence Models for Engineering Applications, AIAA Journal, vol. 32, no. 8.
12. 12. F.R. Menter, M. Kuntz, and R. Langtry, (2003) Ten Years of Industrial Experience with the SST Turbulence Model, Turbulence Heat and Mass Transfer, vol. 4.
13. 13. Sogukpinar, H. (2019) Numerical Investigation of Influence of Diverse Winglet Configuration on Induced Drag. Iranian Journal of Science and Technology, Transactions of Mechanical Engineering 1-13.
14. 14. Sogukpinar, H. (2018). Numerical Calculation of Wind Tip Vortex Formation for Different Wingtip devices. INCAS Bulletin, 10(3).
15. 15. Sogukpinar, H. (2019) Low speed Numerical Aerodynamic Analysis of New Designed 3D transport Aircraft. International Journal of Engineering Technologies, 4(4), 153-160.
16. 16. COMSOL CFD module user guide. http://www.comsol.com. (Access time: February 2022).
17. 17. Cummings, Russell M., Scott A. Morton, and Stefan G. Siegel. (2008) Numerical prediction and wind tunnel experiment for a pitching unmanned combat air vehicle. Aerospace Science and Technology 12.5 355-364.