Journal of Aeronautical Engineering

Journal of Aeronautical Engineering

Evaluation of aerodynamic performance of the geometrical twist by variation the Reynolds number in a flying wing

Document Type : Original Article

Authors
Abstract
The twist is one of the most important parameters in the design of the flying wing and tailless aircraft that causes eliminate some aerodynamic challenge at these categories of aircrafts. The present study was performed for an aerodynamic investigation of the geometrical twist at a subsonic flying wing and evaluate this parameter at different flight phases. The study geometry is a lambda-shaped flying wing that has a wing with a 56-degree sweepback. The twist angle applied on wingtips is washout, which is linearly distributed along the wingspan. The study is conducted in the framework of numerical simulation and based on solving Reynolds-Averaged Navier-Stokes (RANS) equations by finite volume method. The simulation process was performed after validation with experimental data, for twist angles of 0 and 6 degrees and range of attack angles of 5 to 20 degrees; also, to investigate the twist performance in the range of landing and take-off phase and cruise phase, studies have been performed in two different Reynolds numbers. The results show that by applying twist, the aerodynamic efficiency is improved at high angles of attack, but this characteristic will drop significantly at the zero-degree angle of attack. Also, by applying the twist, the conditions required for longitudinal stability are satisfied, and the pitch up phenomenon will be delayed.As speed increases, aerodynamic efficiency improves over a wide range of attack angles; also, aerodynamic efficiency changes due to twist increased, and twist will be more effective. Pitch moment analysis shows that as speed increment, the degree of stability will increase, and the pitch-up behavior will improve.
Keywords

 [1] Qin N., Vavalle, A., Le Moigne, A., Laban, M., Hackett, K., Weinerfelt, P., “Aerodynamic considerations of blended wing body aircraft”, Progress in Aerospace Sciences,  vol. 40, 321-43, 2004
 [2]Navabi M., Kakavand, E., “Combined model-reference adaptive controller for coordinated turn of a tailless aircraft”, Modares Mechanical Engineering,  vol. 15, 117-27, 2015
 [3] Nasir R.E., Kuntjoro, W., Wisnoe, W., “Aerodynamic, stability and flying quality evaluation on a small blended wing-body aircraft with canard foreplanes”, Procedia Technology,  vol. 15, 783-91, 2014
 [4]Wick A.T., Hooker, J.R., Clark, C.M., Plumley, R., Zeune, C., editors. Powered Low Speed Testing of the Hybrid Wing Body2017.
 [5]Wick A.T., Hooker, J.R., Walker, J., Chan, D.T., Plumley, R., Zeune, C., editors. Hybrid Wing Body Performance Validation at the National Transonic Facility. 55th AIAA Aerospace Sciences Meeting; 2017.
 [6]Liebeck R.H., “Design of the blended wing body subsonic transport”, Journal of aircraft,  vol. 41, 10-25, 2004
 [7]Dehpanah P., Nejat, A., “The aerodynamic design evaluation of a blended-wing-body configuration”, Aerospace Science and Technology,  vol. 43, 96-110, 2015
 [8]Martinez-Val R., “Flying wings. A new paradigm for civil aviation?”, Acta Polytechnica,  vol. 47, 2007
 [9]Roskam J. Airplane design: DARcorporation; 1985.
 [10]Liebeck R.H., Page, M.A., Rawdon, B.K., “Evolution of the revolutionary blended-wing-body”, 1996
 [11] Stenfelt G., Ringertz, U., “Yaw control of a tailless aircraft configuration”, Journal of aircraft,  vol. 47, 1807-11, 2010
 [12]Tomac M., Stenfelt, G., “Predictions of stability and control for a flying wing”, Aerospace Science and Technology,  vol. 39, 179-86, 2014
 [13]Davidson R., editor Flight control design and test of the joint unmanned combat air system (J-UCAS) X-45A. AIAA 3rd" Unmanned Unlimited" Technical Conference, Workshop and Exhibit; 2004.
 [14]Gabor O.S., Koreanschi, A., Botez, R.M., “Optimization of an Unmanned Aerial System'wing using a flexible skin morphing wing”, SAE International Journal of Aerospace,  vol. 6, 115-21, 2013
 [15]Esteban S., editor Static and dynamic analysis of an unconventional plane-flying wing. AIAA Atmospheric Flight Mechanics Conference and Exhibit; 2001.
 [16]Barnard R.H., Philpott, D.R. Aircraft flight: a description of the physical principles of aircraft flight: Pearson Education; 2010.
 [17]Dehghan Menshadi M., Eilbeigi, M., Vaziry, M.A., “Experimental investigation on aerodynamic coefficients of a flying wing aircraft with different leading edge sweep angle”, Modares Mechanical Engineering,  vol. 16, 303-11, 2016
 [18]BRETT J., OOI, A., “Effect of Sweep Angle on the Vortical Flow over Delta Wings at an Angle of Attack of 10”, Journal of Engineering Science and Technology,  vol. 9, 768-81, 2014
 [19] Qu X., Zhang, W., Shi, J., Lyu, Y., “A novel yaw control method for flying-wing aircraft in low speed regime”, Aerospace Science and Technology,  vol. 69, 636-49, 2017
 [20]Mader C.A., Martins, J.R., “Stability-constrained aerodynamic shape optimization of flying wings”, Journal of Aircraft,  vol. 50, 1431-49, 2013
 [21]Lyu Z., Martins, J.R., “Aerodynamic design optimization studies of a blended-wing-body aircraft”, Journal of Aircraft, vol. 51, 1604-17, 2014
 [22] Phillips W., “Lifting-line analysis for twisted wings and washout-optimized wings”, Journal of aircraft,  vol. 41, 128-36, 2004
 [23]Phillips W., Fugal, S., Spall, R., editors. Minimizing induced drag with geometric and aerodynamic twist, CFD validation. 43rd AIAA Aerospace Sciences Meeting and Exhibit; 2005.
 [24] Nangia R., Ghoreyshi, M., van Rooij, M.P., Cummings, R.M., “Aerodynamic design assessment and comparisons of the MULDICON UCAV concept”, Aerospace Science and Technology,  vol. 93, 105321, 2019
 [25]Brett J., Tang, L., Hutchins, N., Valiyff, A., Ooi, A., editors. Computational fluid dynamics analysis of the 1303 unmanned combat air vehicle. 17thAustralasian Fluid Mechanics Conference; 2010.
 [26] Stenfelt G., Ringertz, U., “Lateral stability and control of a tailless aircraft configuration”, Journal of Aircraft,  vol. 46, 2161-4, 2009
 [27]Jansson N., Stenfelt, G., “Steady and unsteady pressure measurements on a swept-wing aircraft”, The Aeronautical Journal,  vol. 118, 109-22, 2014
 [28]Fluent A., “Theory Guide 17.2”, Ansys Inc USA, 2016
 [29]Davidson L., Fluid mechanics, turbulent flow and turbulence modeling. Accessed on; 2015.
 [30]Nelson R., Airplane Stability and Automatic Control. New York: McGraw-Hill Book; 1989.