Experiment on Wingtip Vortices using a Half Deltawing at the Tips

The counter rotating wing tip vortices produced by the aircraft continues to be a big concern for the aviation industry and the aircraft manufacturers due to its hazardous effects on the flight safety and aircraft efficiency. The strength of the vortices poses severe problems to the aircraft operations. Manufacturers developed various wingtip devices to alleviate this problem, but still it is not fully understood and solved. In this thesis, the effectiveness of using a half delta wing at the tips is investigated. The flow field over a low aspect ratio NACA 0015 wing fitted with a slender sharp half delta wing with a leading edge sweep angle 700 at a Reynolds number 1.87 ×105 is investigated. Particle image velocimetry is used to quantify the vortex structure and force balance measurements are used to calculate the aerodynamic data of the wing. The peak vorticity, peak tangential velocity are decreased due to the addition of half delta wing. The over-all radius of the wingtip vortex increased showing a diffused vortex due to the addition of the half delta wing. The core circulation is decreased leading to a lower strength vortex. Though the tip device increased the drag, it increases the aerodynamic efficiency through the improvement in L/D

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Investigation on the effect of leading edge tubercles of sweptback wing at low reynolds number

Mechanics & Industry ◽

10.1051/meca/2020095 ◽

2020 ◽

Vol 21 (6) ◽

pp. 621

Author(s):

Veerapathiran Thangaraj Gopinathan ◽

John Bruce Ralphin Rose ◽

Mohanram Surya

Keyword(s):

Leading Edge ◽

Reynolds Numbers ◽

Sweep Angle ◽

Laminar Separation ◽

Low Reynolds Numbers ◽

Flow Energy ◽

Airplane Wing ◽

Low Reynolds ◽

Naca 0015 ◽

Wing Performance

Aerodynamic efficiency of an airplane wing can be improved either by increasing its lift generation tendency or by reducing the drag. Recently, Bio-inspired designs have been received greater attention for the geometric modifications of airplane wings. One of the bio-inspired designs contains sinusoidal Humpback Whale (HW) tubercles, i.e., protuberances exist at the wing leading edge (LE). The tubercles have excellent flow control characteristics at low Reynolds numbers. The present work describes about the effect of tubercles on swept back wing performance at various Angle of Attack (AoA). NACA 0015 and NACA 4415 airfoils are used for swept back wing design with sweep angle about 30°. The modified wings (HUMP 0015 A, HUMP 0015 B, HUMP 4415 A, HUMP 4415 B) are designed with two amplitude to wavelength ratios (η) of 0.1 & 0.24 for the performance analysis. It is a novel effort to analyze the tubercle vortices along the span that induce additional flow energy especially, behind the tubercles peak and trough region. Subsequently, Co-efficient of Lift (CL), Co-efficient of Drag (CD) and boundary layer pressure gradients also predicted for modified and baseline (smooth LE) models in the pre & post-stall regimes. It was observed that the tubercles increase the performance of swept back wings by the enhanced CL/CD ratio in the pre-stall AoA region. Interestingly, the flow separation region behind the centerline of tubercles and formation of Laminar Separation Bubbles (LSB) were asymmetric because of the sweep.

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Vortex flow and lift generation of a non-slender reverse delta wing

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410016671342 ◽

2016 ◽

Vol 231 (13) ◽

pp. 2438-2451

Author(s):

T Lee ◽

LS Ko

Keyword(s):

Particle Image Velocimetry ◽

Lift Force ◽

Vortex Flow ◽

Particle Image ◽

Delta Wing ◽

Lower Surface ◽

Force Balance ◽

Flow Parameters ◽

Image Velocimetry ◽

Spanwise Vortex

The vortex flow and lift force generated by a 50°-sweep non-slender reverse delta wing were investigated via particle image velocimetry, together with flow visualization and force balance measurement, at Re = 11,000. The non-slender reverse delta wing produced a delayed stall but a lower lift compared to its delta wing counterpart. The stalling mechanism was also found to be triggered by the disruption of the multiple spanwise vortex filaments developed over the upper wing surface. The vortex flowfield was, however, characterized by the co-existence of reverse delta wing vortices and multiple shear-layer vortices. The outboard location of the reverse delta wing vortex further implies that the lift force is mainly generated by the wing lower surface while the upper surface acts as a wake generator. The spatial progression of the flow parameters of the vortex generated by the non-slender reverse delta wing as a function of α was also discussed.

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Optimization of Aerodynamic Parameters of Cropped Delta Wing with Fence at Sonic Mach Number

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2019.7740 ◽

2019 ◽

Vol 16 (2) ◽

pp. 403-409

Author(s):

M. P. Arun ◽

M. Satheesh ◽

Edwin Raja J. Dhas

Keyword(s):

Shock Wave ◽

Boundary Condition ◽

Mach Number ◽

Sound Speed ◽

Delta Wing ◽

Leading Edge ◽

Supersonic Speed ◽

Sweep Angle ◽

Ansys Fluent ◽

Aerodynamic Parameters

Manufacturing and maintaining different aircraft fleet leads to various purposes, which consumes more money as well as man power. Solution to this, nations that are leading in the field of aeronautics are performing much research and development works on new aircraft designs that could do the operations those were done by varied aircrafts. The foremost benefit of this delta wing is, along the huge rearward sweep angle, the wing’s leading edge would not contact the boundary of shock wave. Further, the boundary is produced at the fuselage nose due to the speed of aircraft approaches and also goes beyond the transonic to supersonic speed. Further, rearward sweep angle greatly worse the airspeed: wings under normal condition to leading edge, so permits the aircraft to fly at great transonic, subsonic, or supersonic speed, whereas the over wing speed is kept to minimal range than that of the sound speed. The cropped delta wing with fence has analysed in three cases: Fences at 3/4th distance from the centre, with fences at half distance from the centre and with fences at the centre. Further, the delta wing that cropped is exported to ANSYS FLUENT V14.0 software and analysed by making the boundary condition settings like sonic Mach number of flow over wing along with the angle of attack.

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Impact of Gurney Flaplike Strips on the Aerodynamic and Vortex Flow Characteristic of a Reverse Delta Wing

Journal of Fluids Engineering ◽

10.1115/1.4032301 ◽

2016 ◽

Vol 138 (6) ◽

Cited By ~ 7

Author(s):

T. Lee

Keyword(s):

Vortex Flow ◽

Delta Wing ◽

Lift Coefficient ◽

Leading Edge ◽

Aerodynamic Characteristics ◽

Force Balance ◽

Vortex Control ◽

Lift Curve ◽

Lift And Drag ◽

The Impact

The impact of Gurney flaplike strips, of different geometric configurations and heights, on the aerodynamic characteristics and the tip vortices generated by a reverse delta wing (RDW) was investigated via force-balance measurement and particle image velocimetry (PIV). The addition of side-edge strips (SESs) caused a leftward shift of the lift curve, resembling a conventional trailing-edge flap. The large lift increment overwhelmed the corresponding drag increase, thereby leading to an improved lift-to-drag ratio compared to the baseline wing. The lift and drag coefficients were also found to increase with the strip height. The SES-equipped wing also produced a strengthened vortex compared to its baseline wing counterpart. The leading-edge strips (LESs) were, however, found to persistently produce a greatly diffused vortex flow as well as a small-than-baseline-wing lift in the prestall α regime. The downward LES delivered a delayed stall and an increased maximum lift coefficient compared to the baseline wing. The LESs provide a potential wingtip vortex control alternative, while the SESs can enhance the aerodynamic performance of the RDW.

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Experimental Control of Vortex Breakdown by Pulsed Blowing Over a Delta Wing With Rounded Leading-Edge

Volume 1: Fora, Parts A and B ◽

10.1115/fedsm2002-31039 ◽

2002 ◽

Cited By ~ 1

Author(s):

Renac Florent ◽

Molton Pascal ◽

Barberis Didier

Keyword(s):

Vortex Breakdown ◽

Delta Wing ◽

Laser Sheet ◽

Leading Edge ◽

Control Device ◽

Surface Flow ◽

Sweep Angle ◽

Laminar To Turbulent Transition ◽

Pressure Distributions ◽

Oil Flow

The purpose of this study is to construct and test an experimental device to control vortex on a delta wing. The model has a root chord of c = 690mm and a sweep angle of Λ = 60°. The control system is based on four rectangular slits 50 mm long and 0.2 mm wide running along the leading edge. This configuration produces jets normal to the leading edge. The mass flow rates and frequencies of injection can be varied independently. The results are shown in the form of surface flow visualizations, with the skin friction pattern exhibited by oil flow visualization, and the laminar-to-turbulent transition by acenaphthene. Mean and instantaneous surface pressure distributions were determined with Kulite™ sensors and the velocity field was determined by 3D laser Doppler velocimetry (LDV) measurements. Control device efficiencies were evaluated by laser sheet visualization.

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Alleviation of pitch-up on delta wings using distributed porosity

The Aeronautical Journal ◽

10.1017/s000192400006471x ◽

1999 ◽

Vol 103 (1025) ◽

pp. 339-347 ◽

Cited By ~ 3

Author(s):

L. W. Traub ◽

B. Moeller ◽

S. F. Galls

Keyword(s):

Experimental Investigation ◽

Flow Field ◽

Delta Wing ◽

Leading Edge ◽

Surface Flow ◽

Force Balance ◽

Flow Visualisation ◽

Surface Porosity ◽

Delta Wings ◽

Field Surveys

Abstract An experimental investigation was undertaken to determine the effectiveness of distributed surface porosity for the alleviation of pitch-up on a delta wing. Tests were undertaken using a 65° sweep delta wing with distributed porosity evaluated at various locations on the wing. Force balance, on and off surface flow visualisation and flow field surveys using a multi-hole probe were undertaken. The data shows that distributed porosity applied along the wing leading edge at the apex is effective in eliminating pitch-up whilst incurring a minimal performance cost. Trailing edge porosity generally degraded performance.

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The Leading-Edge Vortex of Swift Wings

10.1101/099713 ◽

2017 ◽

Author(s):

Rowan Eveline Muir ◽

Ignazio Maria Viola

Keyword(s):

Vortex Breakdown ◽

Delta Wing ◽

Leading Edge ◽

Leading Edge Vortex ◽

Wing Model ◽

Image Velocimetry ◽

Edge Vortex ◽

First Time ◽

Swept Wings ◽

Sharp Leading Edge

1AbstractRecent investigations on the aerodynamics of natural fliers have illuminated the significance of the Leading-Edge Vortex (LEV) for lift generation in a variety of flight conditions. A well documented example of an LEV is that generated by aircraft with highly swept, delta shaped wings. While the wing aerodynamics of a manoeuvring aircraft, a bird gliding and a bird in flapping flight vary significantly, it is believed that this existing knowledge will serve to add understanding to the complex aerodynamics of natural fliers. In this investigation, the wing of a common swift Apus apus is simplified to a model with swept wings and a sharp leading-edge, making it readily comparable to a model delta shaped wing of the same leading-edge geometry. Particle image velocimetry provides an understanding of the effect of the tapering swift wing on LEV development and stability, compared with the delta wing model. For the first time a dual LEV is recorded on a swift shaped wing, where it is found across all tested conditions. It is shown that the span-wise location of LEV breakdown is governed by the local chord rather than Reynolds number or angle of attack. These findings suggest that the common swift is able to generate a dual LEV while gliding, potentially delaying vortex breakdown by exploiting other features non explored here, such as wing twist and flexibility. It is further suggested that the vortex system could be used to damp loading fluctuations, reducing energy expenditure, rather than for lift augmentation.

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The leading-edge vortex of swift wing-shaped delta wings

Royal Society Open Science ◽

10.1098/rsos.170077 ◽

2017 ◽

Vol 4 (8) ◽

pp. 170077 ◽

Cited By ~ 7

Author(s):

Rowan Eveline Muir ◽

Abel Arredondo-Galeana ◽

Ignazio Maria Viola

Keyword(s):

Reynolds Number ◽

Delta Wing ◽

Leading Edge ◽

Trailing Edge ◽

Delta Wings ◽

Leading Edge Vortex ◽

Wing Model ◽

Image Velocimetry ◽

Edge Vortex ◽

First Time

Recent investigations on the aerodynamics of natural fliers have illuminated the significance of the leading-edge vortex (LEV) for lift generation in a variety of flight conditions. A well-documented example of an LEV is that generated by aircraft with highly swept, delta-shaped wings. While the wing aerodynamics of a manoeuvring aircraft, a bird gliding and a bird in flapping flight vary significantly, it is believed that this existing knowledge can serve to add understanding to the complex aerodynamics of natural fliers. In this investigation, a model non-slender delta-shaped wing with a sharp leading edge is tested at low Reynolds number, along with a delta wing of the same design, but with a modified trailing edge inspired by the wing of a common swift Apus apus . The effect of the tapering swift wing on LEV development and stability is compared with the flow structure over the unmodified delta wing model through particle image velocimetry. For the first time, a leading-edge vortex system consisting of a dual or triple LEV is recorded on a swift wing-shaped delta wing, where such a system is found across all tested conditions. It is shown that the spanwise location of LEV breakdown is governed by the local chord rather than Reynolds number or angle of attack. These findings suggest that the trailing-edge geometry of the swift wing alone does not prevent the common swift from generating an LEV system comparable with that of a delta-shaped wing.

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Leading-edge vortices over swept-back wings with varying sweep geometries

Royal Society Open Science ◽

10.1098/rsos.190514 ◽

2019 ◽

Vol 6 (7) ◽

pp. 190514 ◽

Cited By ~ 1

Author(s):

William B. Lambert ◽

Mathew J. Stanek ◽

Roi Gurka ◽

Erin E. Hackett

Keyword(s):

Particle Image ◽

Delta Wing ◽

Leading Edge ◽

Micro Air Vehicles ◽

Linear Sweep ◽

Image Velocimetry ◽

Gliding Flight ◽

Swirling Strength ◽

The Common ◽

Leading Edge Vortices

Micro air vehicles are used in a myriad of applications, such as transportation and surveying. Their performance can be improved through the study of wing designs and lift generation techniques including leading-edge vortices (LEVs). Observation of natural fliers, e.g. birds and bats, has shown that LEVs are a major contributor to lift during flapping flight, and the common swift ( Apus apus ) has been observed to generate LEVs during gliding flight. We hypothesize that nonlinear swept-back wings generate a vortex in the leading-edge region, which can augment the lift in a similar manner to linear swept-back wings (i.e. delta wing) during gliding flight. Particle image velocimetry experiments were performed in a water flume to compare flow over two wing geometries: one with a nonlinear sweep (swift-like wing) and one with a linear sweep (delta wing). Experiments were performed at three spanwise planes and three angles of attack at a chord-based Reynolds number of 26 000. Streamlines, vorticity, swirling strength, and Q -criterion were used to identify LEVs. The results show similar LEV characteristics for delta and swift-like wing geometries. These similarities suggest that sweep geometries other than a linear sweep (i.e. delta wing) are capable of creating LEVs during gliding flight.

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