Transformation of flow structure on a delta wing of moderate sweep angle during pitch-up maneuver

The transformation of flow structure on a delta wing of moderate sweep angle is investigated during pitch-up via quantitative imaging in crossflow planes, in relation to qualitative dye visualization. The comparisons are made with the corresponding stationary wing. The effects of different pitch-up maneuver rates and Reynolds numbers on evolution of flow patterns are also addressed. A technique of high-image-density particle image velocimetry is employed for the quantitative analysis. The transformation of the flow structure starts with intertwining of the dual vortex structure which is distinctively seen at a low angle of attack of 50 swept wing, and then continues with the disappearance of one of the vortices of the dual vortex structure, in particular, the vortex located closest to the leading-edge of the wing. At further stages, a single, large-scale, leading-edge vortex, and distinctive form of vortex breakdown is witnessed. This distinctive type of vortex breakdown turns into a more traditional form at later stages of the maneuver. During the final stage of the pitch-up maneuver, the onset of vortex breakdown moves toward the apex of the wing. The general trend of aforementioned flow transformation happens irrespective of the values of pitch rates and Reynolds numbers. When the foregoing patterns are compared with the corresponding patterns on the stationary wing, it is evident that a significant time lag of development of the flow patterns occurs, relative to the motion of the wing.


Computation of Vortical Flow Fields over a Close-Coupled Delta Canard-Wing Configuration and Adjoint Based Configuration Optimization
Tikenoğulları, Alp; Tuncer, İsmail Hakkı; Department of Aerospace Engineering (2022-2-10)
This study aims at investigating the vortical flow field over a close-coupled delta canard-wing configuration to understand the vortex interactions and the mechanism of lift enhancement provided by the canard, especially at high angles of attack, and employing an adjoint-based configuration optimization to achieve further enhancements in aerodynamic forces. An open-source CFD solver, SU2 is employed for both flow field computations and adjoint-based configuration optimizations. First, flow solutions with SU...
Effect of thickness-to-chord ratio on aerodynamics of non-slender delta wing
Ghazijahani, Mohammad Sharifi; Yavuz, Mehmet Metin (2019-05-01)
The effect of thickness-to-chord (t/C) ratio on aerodynamics of a non-slender delta wing with sweep angle of 45 degree is characterized in a low-speed wind tunnel using laser illuminated smoke visualization, surface pressure measurements, particle image velocimetry, and force measurements. The delta wings of t/C ratios varying from 2% to 15% with 45 degree windward beveled leading edges are tested. The results indicate that the effect of t/C ratio on flow structure is quite substantial. Considering the low ...
Effect of ground on aerodynamics and longitudinal static stability of a non-slender delta wing
Koçak, Göktuğ; Yavuz, Mehmet Metin (2022-11-01)
© 2022 Elsevier Masson SASIn this paper, the effect of ground on aerodynamics and longitudinal static stability of a non-slender delta wing with sweep angle of 45 degree and thickness-to-chord ratio (t/c) of 5.9% was characterized at Reynolds number of 9×104 in a low-speed wind tunnel using force and pressure measurements. The measurements were conducted for angles of attack varying between 0≤α≤30 degrees and non-dimensional heights between 3%≤h/c≤107% and height stability of the wing based on aerodynamic c...
Flow Structure on Nonslender Delta Wing: Reynolds Number Dependence and Flow Control
Zharfa, Mohammadreza; Ozturk, Ilhan; Yavuz, Mehmet Metin (2016-03-01)
The flow structure over a 35 deg swept delta wing is characterized in a low-speed wind tunnel using techniques of laser-illuminated smoke visualization, laser Doppler anemometry, and surface-pressure measurements. The effects of Reynolds numbers and attack angles on the evaluation of flow patterns are addressed within the broad range of Reynolds number 10(4) < Re < 10(5) and attack angle 3 deg < alpha < 10 deg. In addition, the effect of steady blowing through the leading edges of the wing on flow structure...
Effect of ground on flow structure of non-slender delta and reverse delta wings
Koçak, Göktuğ; Yavuz, Mehmet Metin; Department of Mechanical Engineering (2023-1-26)
Flight condition of aircrafts proximity to the ground, so-called “Ground Effect” (GE), is among one of the most recent research areas since the aerodynamic performance and stability of wing in ground effect (WIG) crafts significantly vary due to the flow dynamics associated with the interaction between the wing and the surface. In the present study, ground effect of non-slender delta wings (DW) and reversed delta wings (RDW) at static ground effect (SGE) condition in the absence of heave and pitch motion w...
Citation Formats
M. M. Yavuz, “Transformation of flow structure on a delta wing of moderate sweep angle during pitch-up maneuver,” JOURNAL OF FLUIDS AND STRUCTURES, pp. 59–69, 2012, Accessed: 00, 2020. [Online]. Available: