Effect of Airfoil-Preserved Undulation Placement on Wing Performance and Wingtip Vortex

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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Numerical Study of Unsteady Low-Reynolds Number Wing Performance

10.21236/ada479418 ◽

2008 ◽

Author(s):

Ashok Gopalarothnam ◽

Gregory Z. McGowan

Keyword(s):

Reynolds Number ◽

Numerical Study ◽

Low Reynolds Number ◽

Low Reynolds ◽

Wing Performance

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Fluid–structure interaction simulation on flight performance of a dragonfly wing under different pterostigma weights

Journal of Mechanics ◽

10.1093/jom/ufaa013 ◽

2021 ◽

Vol 37 ◽

pp. 216-229

Author(s):

Yung Jeh Chu ◽

Poo Balan Ganesan ◽

Mohamad Azlin Ali

Keyword(s):

Optimization Design ◽

Fluid Structure Interaction ◽

Spatial Location ◽

Fluid Structure ◽

Structure Interaction ◽

Dragonfly Wing ◽

Interaction Simulation ◽

Wing Performance ◽

Drag Ratio ◽

Lift To Drag Ratio

Abstract The dragonfly wings provide insights for designing an efficient biomimetic micro air vehicle (BMAV). In this regard, this study focuses on investigating the effect of the pterostigma weight loading and its spatial location on the forewings of dragonfly by using the fluid–structure interaction simulation. This study also investigates the effect of change in the wing elasticity and density on the wing performance. The forewing, which mimics the real dragonfly wing, is flat with a 47.5 mm span and a 0.4 mm thickness. The wing was set to cruise at 3 m/s with a constant flapping motion at a frequency of 25 Hz. This study shows that a small increase of pterostigma loading (11% of wing weight) at the tip of the wing significantly improves the lift to drag ratio, CL/CD, which has 129.16% increment in comparison with no loading. The lift to drag ratio depends on the pterostigma location, pterostigma loading, elastic modulus and density. The results of this study can be used as a reference in future BMAV wing optimization design.

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Scaling Analysis on the Dynamic and Instability Characteristics of Isolated Wingtip Vortex

AIAA Journal ◽

10.2514/1.j060281 ◽

2021 ◽

pp. 1-13

Author(s):

Yang Xiang ◽

Ze-Peng Cheng ◽

Yi-Ming Wu ◽

Hong Liu ◽

Fuxin Wang

Keyword(s):

Scaling Analysis ◽

Wingtip Vortex

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Broken-Wing Performance by the Eastern Willet

The Auk ◽

10.2307/4078910 ◽

1941 ◽

Vol 58 (1) ◽

pp. 95-95

Author(s):

Ivan R. Tomkins

Keyword(s):

Wing Performance

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Next Steps Envisaged to Improve Wing Performance of Commercial Aircrafts

Aerodynamic Drag Reduction Technologies ◽

10.1007/978-3-540-45359-8_26 ◽

2001 ◽

pp. 246-255

Author(s):

Josef Mertens

Keyword(s):

Wing Performance ◽

Commercial Aircrafts

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Experimental investigation on the structures and induced drag of wingtip vortices for different wingtip configurations

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

10.1177/0954410020947911 ◽

2020 ◽

pp. 095441002094791

Author(s):

Ze-Peng Cheng ◽

Yang Xiang ◽

Hong Liu

Keyword(s):

Growth Rate ◽

Form Factor ◽

Drag Coefficient ◽

Particle Image ◽

Vortex Center ◽

Streamwise Location ◽

Induced Drag ◽

Wingtip Vortex ◽

Image Velocimetry ◽

Drag And Lift

As an effective method to reduce induced drag and the risk of wake encounter, the winglet has been an essential device and developed into diverse configurations. However, the structures and induced drag, as well as wandering features of the wingtip vortices ( WTVs) generated by these diverse winglet configurations are not well understood. Thus, the WTVs generated by four typical wingtip configurations, namely the rectangular wing with blended/raked/split winglet and without winglet (Model BL/ RA/ SP/NO for short), are investigated in this paper using particle image velocimetry technology. Comparing with an isolated primary wingtip vortex generated by Model NO, multiple vortices are twisted coherently after installing the winglets. In addition, the circulation evolution of WTVs demonstrates that the circulation for Model SP is the largest, while Model RA is the smallest. By tracking the instantaneous vortex center, the vortex wandering behavior is observed. The growth rate of wandering amplitude along with the streamwise location from the quickest to the slowest corresponds to Model SP, Model NO, Model BL, Model RA in sequence, implying that the WTVs generated by model SP exhibit the quickest mitigation. Considering that the induced drag scales as the lift to power 2, the induced drag and lift are estimated based on the wake integration method, and then the form factor λ, defined by [Formula: see text], is calculated to evaluate the aerodynamic performance. Comparing with the result of Model NO, the form factor decreases by 7.99%, 4.80%, and 2.60% for Model RA, Model BL, Model SP, respectively. In sum, Model RA and BL have a smaller induced drag coefficient but decay slower; while Model SP has a larger induced drag coefficient but decays quicker. An important implication of these results is that reducing the strength of WTVs and increasing the growth rate of vortex wandering amplitude can be the mutual requirements for designing new winglets.

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