Numerical investigation of thickness-to-chord ratio on aerodynamic characteristics and flow field of a low swept delta wing

Download

index.pdf

Date

2019

Author

Cesur, İsmail Sadi

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

375
views

185
downloads

Recent years revealed the increased interest in Unmanned Combat Air Vehicles (UCAVs) and Unmanned Air Vehicles (UAVs) which utilize delta wing planforms, making the Delta wing studies more prominent. Delta wings are characterized by two counter-rotating vortices on leading edges formed by the detached shear layer from the windward side of the planform. Those vortical structures lower the pressures on the suction side of the wing therefore contributes to the increase of the lifting and maneuvering capacity of the wing. Present study, involving Computational Fluid Dynamics (CFD) simulations, investigates the effects of the thickness-to-chord ratio of a low swept delta wing on the aerodynamic characteristics and the flow field. In the present study, a delta wing planform having a 35 degrees of sweep angle with two thickness-to-chord ratios are numerically examined at Reynolds Numbers, RE = 35000 & 300000 and angles of attack ranging from 4° to 40°. A mesh independence study is conducted and CFD results are validated by the data of an experimental study. SST k-ω turbulence model with the extension of curvature correction function is utilized due to its success of yielding the most accurate results. When flow field results are investigated it is seen that the vortex breakdown phenomena and three-dimensional flow separation occur much sooner with the increase of both thickness-to-chord ratio and Reynolds number, such that in some cases steady vortex structure breaks down right at the apex of the wing. The results also indicate that thickness-to-chord ratio has a significant effect on the aerodynamic coefficients and the flow field, such that, with the increase in t/c ratio drag coefficient, CD increases at all angles of attack, ratio of the lift and drag coefficients, CL/CD decreases. Moreover, CL and Cm values are decreasing with the increase of t/c ratio with the exception for the region till the stall angle of attack is reached. Post stall values of CL and Cm are higher for the thin wing. With the increase in the Reynolds number, all aerodynamic coefficients are increased when it is compared to the lower Reynolds Number results. However, individual trend of the aerodynamic coefficients mentioned above remains the same. To conclude, the aerodynamic coefficients and flow field are highly affected by the thickness-to-chord ratio, which in turn might prove to be a useful tool to control the flow field, and a step to improve the numerical calculation methods to acquire the vortical structures.

Subject Keywords

Leading edges (Aerodynamics)., Delta Wing, Leading Edge Vortices, CFD, Thickness Effects, Vortex Breakdown, Aerodynamics.

URI

http://etd.lib.metu.edu.tr/upload/12623904/index.pdf
https://hdl.handle.net/11511/44472

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Numerical investigation of thickness-to-chord ratio on aerodynamic characteristics and flow field of a low swept delta wing Cesur, İsmail Sadi; Albayrak, Kahraman; Department of Mechanical Engineering (2019) Recent years revealed the increased interest in Unmanned Combat Air Vehicles (UCAVs) and Unmanned Air Vehicles (UAVs) which utilize delta wing planforms, making the Delta wing studies more prominent. Delta wings are characterized by two counter-rotating vortices on leading edges formed by the detached shear layer from the windward side of the planform. Those vortical structures lower the pressures on the suction side of the wing therefore contributes to the increase of the lifting and maneuvering capacity o...
Control of flow structure on 70° swept delta wing with along-the-core blowing using numerical modeling Küçükyılmaz, İbrahim Can; Yavuz, Mehmet Metin; Department of Mechanical Engineering (2016) In recent years, interest has increased in Unmanned Combat Air Vehicles (UCAVs) and Unmanned Air Vehicles (UAVs), which can be represented by simplified planforms including delta wings. Delta wings experience the formation of two counter-rotating vortices on the leeward side of the planform due to the shear layer separated from the windward side. At sufficiently high angle of attack, these vortices undergo sudden expansion, called vortex breakdown/burst, which is quite detrimental considering the aerodynami...
Effect of thickness-to-chord ratio on aerodynamics of non-slender delta wing Sharifi Ghazijahani, Mohammad; Yavuz, Mehmet Metin; Department of Mechanical Engineering (2018) Flow characterization over delta wings have gained attention in recent decades due to their prevailing usage in designs of unmanned air vehicles (UAVs). In literature,only a few studies have reported wing thickness effect on both the aerodynamic performance and detailed flow structure over delta wings. In the present investigation, the effect of thickness-to-chord (t/C) ratio on aerodynamics of a non-slender delta wing with 45 degree sweep angle is characterized in a low-speed wind tunnel using laser illumi...
Development and implementation of novel flow control techniques for nonslender delta wings Çelik, Alper; Yavuz, Mehmet Metin; Department of Mechanical Engineering (2017) Understanding and controlling the physical phenomenon behind the aerodynamics of low to moderate swept delta wings has been a challenge for researchers during the last few decades, which is stimulated by their widespread use in unmanned combat air vehicles (UCAVs) and micro air vehicles (MAVs). Although delta wings are capable of generating high lift and stable flight performance at high angle of attack, the problems related to lack of conventional flow control surfaces compel the researchers to explore new...
Control of flow structure on low swept delta wing with staedy leading edge blowing Zharfa, Mohammadreza; Yavuz, Mehmet Metin; Department of Mechanical Engineering (2014) Unmanned Combat Air Vehicles (UCAVs), Unmanned Air Vehicles (UAVs) and Micro Air Vehicles are becoming extremely popular due to introducing many advantages to defense industry and aeronautical field. In line with this, the aerodynamics of these vehicles, which can be represented by simplified planforms, including delta wings, have been of considerable interest in recent years. This interest has stimulated investigation of the flow structure, as well as its control, on delta wings having low and moderate val...

Citation Formats

İ. S. Cesur, “Numerical investigation of thickness-to-chord ratio on aerodynamic characteristics and flow field of a low swept delta wing,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Mechanical Engineering., Middle East Technical University, 2019.