Performance augmentation mechanism of tandem flapping foils with stroke time-asymmetry

Wang, Guangjian; Ng, Bing Feng; Teo, Zhen Wei; Lua, Kim Boon; Bao, Yan

doi:10.1016/j.ast.2021.106939

Cited by 18 publications

(3 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The findings of this study were the tandem airfoils generated a higher lift and drag compared to isolated airfoils and that the optimal spacing between airfoils is from 1.5c to 2c. The same elliptical airfoils and Re = 5000 but undergoing time-asymmetric flapping and various phase angles were studied by Wang et al [31]. Bie [3] also studied tandem NACA 0012 airfoils at Re = 34,410 that underwent pitch and plunge motions.…”

Section: Introductionmentioning

confidence: 97%

Numerical Analysis on The Effects of Stagger, Thickness, and Curvature on The Propulsion of Tandem Airfoil

Zebua,

Tobing,

Nur

et al. 2023

Int. J. Automot. Mech. Eng.

View full text Add to dashboard Cite

The study of the aerodynamics of flapping airfoils is crucial to understand the flight of natural flyers and its potential applications in developing micro air vehicles and wind/water turbine blades. There has been much research on the aerodynamics of flapping wings recently, but there is only a little research relating to the tandem airfoil. Therefore, this study is conducted to determine the aerodynamic characteristics of the tandem airfoil at Re = 100000, typical of insect flight. The tandem airfoil is plunging and pitching harmonically. This study numerically analyzes the effects of stagger, thickness, and curvature on tandem airfoil propulsion. The effects of stagger are studied using NACA 0012, while the effects of thickness are analyzed on NACA 0012, 0015, 0020 and 0030. The simulations to study the effects of curvature are conducted using NACA 0030. The optimum distance of the stagger is X/c = 2.5, but the propulsive efficiency of tandem NACA 0012 is still smaller than two single NACA 0012 airfoils. For the most optimum thickness at 30% of the chord length, the propulsive efficiency of tandem NACA 0030 is higher than two single NACA 0030 airfoils. Meanwhile, the most optimum curvature is 0% because the increase in curvature of the airfoil reduces propulsive efficiency.

show abstract

Section: Introductionmentioning

confidence: 97%

Numerical Analysis on The Effects of Stagger, Thickness, and Curvature on The Propulsion of Tandem Airfoil

Zebua,

Tobing,

Nur

et al. 2023

Int. J. Automot. Mech. Eng.

View full text Add to dashboard Cite

show abstract

“…Both in-phase and out-of-phase oscillations were considered at high St and found to exhibit unsteady behavior with distinct wake characteristics. The influence of Strouhal number and stream-wise gap for a tandem foil configuration has also received some attention in the literature [34][35][36][37] .…”

Section: Introductionmentioning

confidence: 99%

Effect of combined heaving and pitching on propulsion of single and tandem flapping foils

Hegde¹,

Gurugubelli²,

Joshi³

2022

Preprint

View full text Add to dashboard Cite

Flow dynamics across flapping foils in tandem arrangement at Reynolds number of Re = 1100 has been numerically investigated in the present study. The kinematic motion of the foils consists of sinusoidal heaving and pitching motion. The two-dimensional computation has been carried out through the arbitrary Lagrangian-Eulerian (ALE) moving mesh based algorithm with the variational modeling of the incompressible flow equations. The effects of the heave amplitude, pitch amplitude and the flapping frequency on the propulsive performance have been comprehensively studied for a single as well as tandem system of foils at two gaps of 4 and 7 times the downstream foil's chord length. It is found that the effective angle of attack, effective projected area, type of vortex interaction and the timing of the interaction during the downstroke of the flapping motion influence the propulsive performance. Increasing the heave amplitude of the upstream foil leads to an increase in the average thrust generated by the downstream foil for the gap of 7, while the opposite effect is observed for gap of 4. The propulsion of the downstream foil increases monotonically with the heave amplitude of the downstream foil. Upstream foil's pitch amplitude is noticed to have a minor effect on the performance of the downstream foil, while an increase in the pitch amplitude of the downstream foil increases the thrust for larger gap between the foils. The study of the propulsive performance in the frequency-pitch amplitude parametric space for the tandem foils has been performed for the first time, where a more complex behavior is observed. The trends in the thrust coefficient and the propulsive efficiency are corroborated by the study of various vortex interaction mechanisms leading to favorable or unfavorable thrust generating conditions. Finally, the three-dimensional flapping dynamics of the tandem configuration is demonstrated, where no spanwise wake structures are noted, indicating the wake interaction to be inherently two-dimensional.

show abstract

“…Therefore, the unsteady Reynolds-averaged Navier-Stokes (URANS) equations are solved using the finite volume method, where the SST K-ω model is adopted to account for the turbulence effects. To implement the hydrofoil flapping kinematics in the numerical modeling, the overset mesh method is utilized as it outperforms in large rigid-body displacements [130] through data interpolation on the overlapping boundaries. As illustrated in Figure 3.23(a), the computational domain, which is a rectangular area of 3.0 m × 0.45 m, mainly consists of three components with two hydrofoil sub-domains overlapping on a background domain.…”

Section: Computational Setupmentioning

confidence: 99%

Constructive foil-wake Interactions of tandem flapping hydrofoils for propulsion and energy harvesting

Wang

View full text Add to dashboard Cite

First and foremost, I would like to express my heartfelt gratitude to my supervisor, Assistant Professor Ng Bing Feng, for his invaluable advice, continuous support, and patience during the course of my PhD degree. Prof. Ng has provided effective guidance on my research and academic writing. His immense knowledge and plentiful experience have encouraged me in all the time of my academic research.Moreover, I would like to thank Prof. Lua Kim Boon, for his guidance and thought-provoking discussions, which are influential to my research. I also thank Dr.

show abstract

Performance augmentation mechanism of tandem flapping foils with stroke time-asymmetry

Cited by 18 publications

References 38 publications

Numerical Analysis on The Effects of Stagger, Thickness, and Curvature on The Propulsion of Tandem Airfoil

Numerical Analysis on The Effects of Stagger, Thickness, and Curvature on The Propulsion of Tandem Airfoil

Effect of combined heaving and pitching on propulsion of single and tandem flapping foils

Constructive foil-wake Interactions of tandem flapping hydrofoils for propulsion and energy harvesting

Contact Info

Product

Resources

About