Open Access Open Access  Restricted Access Subscription or Fee Access

Experimental Investigation on Blunt-Edged UTM Delta Wing VFE-2 Configurations at Low Reynolds Number


(*) Corresponding author


Authors' affiliations


DOI: https://doi.org/10.15866/ireme.v12i3.13235

Abstract


The flow behaviour over the upper surface of a blunt-edged delta wing is mainly governed by a complicated leading edge vortex. This paper presents an experimental investigation on blunt-edged UTM VFE-2 delta wing model at low Reynolds numbers. The primary vortex for sharp-edged delta wing develops in the apex region even at low angles of attack. However, this situation does not happen for blunt-edged wings; the primary vortex in the leading edge region develops at a certain chordwise position on the wing. The primary vortex progresses upstream or downstream depending on the leading edge profile, the angle of attack and Reynolds number.  A decrease in Reynolds number will accelerate the upstream progression of the primary vortex towards the wing apex. In the VFE-2 research group, many experiments were conducted at  Reynolds number of 1×10^6 and above. Thus, the main objective of this study was to investigate the upstream progression of leading edge primary vortex on a blunt-edged delta wing at Reynolds numbers of 0.5×10^6, 0.75×10^6 and 1.0×10^6. Wind tunnel experiments were performed at three different flow velocities, 8.7 m/s, 13.1 m/s and 17.5 m/s corresponding to Reynolds numbers of 0.5×10^6, 0.75×10^6 and 1.0×10^6. Two measurement techniques were employed on the upper surface of the wing, i.e. experimental surface pressure and tuft techniques. Experiments were also conducted on two different leading edge profiles namely medium and large radius profiles with different leading edge radius-to-wing chord ratio. Pressure coefficients on the upper surface of the wing were plotted to observe the characteristic primary vortex, the upstream progression of the primary vortex and also the characteristics of vortex breakdown. The results obtained indicate that the primary vortex rapidly formed when the Reynolds number was decreased. Analysis in the apex region showed that the attached flow still existed even at a very low Reynolds number of 0.5 × 10^6.
Copyright © 2018 Praise Worthy Prize - All rights reserved.

Keywords


Delta Wing; VFE-2; Primary Vortex; Low Reynolds Number

Full Text:

PDF


References


D. Hummel, Effects of Boundary Layer Formation on The Vortical Flow Above Slender Delta Wings. RTO specialist Meeting on Enhancement of NATO military Flight Vehicle Performance by Management of Interacting Boundary Layer Transition and Separation. Meeting Proceedings RTO-MPAVT-111. 30-1 - 30-2, 2008.

Gad-El-Hak, M. and Blackwelder, R. F., The discrete Vortices from a Delta Wing. Technical Report 1985, Vol. 23, pp. 961-962, 1985.

J. E. Lamar, D. Hummel, Chapter 1 – RTO Task Group AVT-113 Understanding and modelling Vortical Flows to Improve the Technology readiness Level for Military Aircraft: Objectives and Overview. RTO-TR-AVT-113, 2008.

J. Chu, and J. M. Luckring, Experimental Surface Pressure Data Obtained on 65° Delta Wing across Reynolds Number and Mach number Ranges. NASA Technical Memorandum 4645, 1996.

D. Hummel, The Second International Vortex Flow Experiment (VFE-2): Objectives and First Results. Proc. ImechE Vol. 220 Part G: J. Aerospace Engineering, 2006.
http://dx.doi.org/10.1243/09544100jaero72

D. Hummel, The Second International Vortex Flow Experiment (VFE-2): Objectives and Present Status. 25th AIAA Applied Aerodynamics Conference. AIAA 2007-4446, 2007.
http://dx.doi.org/10.2514/6.2007-4446

J. M. Luckring, and D. Hummel, Chapter 24 – What was learned from the new VFE-2 experiments. RTO-TRAVT-113, 2008.

S. B. Mat, The analysis of flow on round-edged delta wings, Ph.D. dissertation, Dept. Aerospace Eng., Univ. of Glasgow, UK, 2011.

S. B. Mat, R. Green, R. Galbraith, F. Coton, The effect of edge profile on delta wing flow. Proc. ImechE Vol. 0(0) Part G: J. Aerospace Engineering, 2016.

R. Konrath, C. Klein, R.H. Engler, and D. Otter, Analysis of PSP Results Obtained for the VFE-2 65° Delta Wing Configuration at Sub- and Transonic Speeds. 24th Applied Aerodynamics Conference. 5-8 June, 2006, San Francisco, California, AIAA 2006-3003.

R. Konrath, C. Klein, A. Schröder, and K.D. Groot, Chapter 19 – Experimental Investigations on the VFE-2 configuration at DLR, Germany, RTO-TR-AVT-113 Technical Report, 19-1 – 19-37, 2009.

J.M. Luckring, Chapter 18 – Intial Experiments and Analysis of Blunt-edge Vortex flow. RTO-TRAVT-113, 2008.

M. Said, S. Mat, S. Mansor, A. A. Latif, and T. M. Lazim, Reynolds Number Effects on Flow Topology Above Blunt-Edge Delta Wing VFE-2 Configurations. 53rd AIAA Aerospace Sciences Meeting, 2015.
http://dx.doi.org/10.2514/6.2015-1229

M. Said, Effects of Leading Edge Radius, Reynolds Number and Angle of Attack on the Vortex Formation above Large-Edged Delta Wing, Master thesis, Dept. Aeronautics, Automotive & Ocean, Universiti Teknologi Malaysia, 2016.

Said, M. and Mat, S., (2016). Effects of Reynolds Number on The Onset of Leading Edge Vortex Separation Above Blunt-edge Delta Wing VFE-2 Configurations. 30th Congress of the International Council of the Aeronautical Sciences. 25–30 September. Daejeon, South Korea. 2016_0608.

Hitzel, S.M. (2013). Perform and Survive – Evolution of Some UCAV Platform Requirements. STO AVT Workshop on Innovative Control Effectors for Military Vehicles. Stockholm, Sweden. 20 – 22 May. No.1, STO-MP-AVT-215.

Luckring, J. M, Boelens, O. J., Breitsamter, C., Hövelmann, A., Knoth, F., Malloy, D. J., Decke, S. (2016). Objectives, approach, and scope for the AVT-183 diamond-wing investigations. Aerospace Science and Technology. Vol. 57. Page 2 – 17.
http://dx.doi.org/10.1016/j.ast.2016.05.025

Tajuddin, N., Mat, S., Said, M. and Mansor, S. (2017). Flow Characteristic of Blunt-edged Delta Wing at High Angle of Attack, Journal of Advanced Research in Fluid Mechanics and Thermal Sciences. Vol. 39. Issue 1. Page 17-25.

Aziz, M., Elsayed, A., CFD Investigations for UAV and MAV Low Speed Airfoils Characteristics, (2015) International Review of Aerospace Engineering (IREASE), 8 (3), pp. 95-100.
http://dx.doi.org/10.15866/irease.v8i3.6212

Ahmed, N., Forward Facing Flap for Delta Wing Performance Improvement, (2017) International Review of Aerospace Engineering (IREASE), 10 (2), pp. 90-95.
http://dx.doi.org/10.15866/irease.v10i2.11512


Refbacks

  • There are currently no refbacks.



Please send any question about this web site to info@praiseworthyprize.com
Copyright © 2005-2024 Praise Worthy Prize