An empirically-based model for the lift coefficients of twisted airfoils with leading-edge tubercles

Ni, Zao; Su, Tsung-Chow; Dhanak, Manhar R.

doi:10.1063/1.5023103

Cited by 8 publications

(1 citation statement)

References 21 publications

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“…However, the CVPs cannot ensure a completely attached flow regime throughout the tubercle airfoil span. Several researchers have additionally reported the intermittent appearance of large separation zones or stall cells 4,13,25,30,38 on the tubercle airfoil. Interestingly, it has been found that the development of these CVPs and stall cells depends on parameters like A, k, and a.…”

Section: Introductionmentioning

confidence: 99%

On the investigation of the aerodynamics performance and associated flow physics of the optimized tubercle airfoil

Pinapatruni,

Duddupudi,

Dash

et al. 2024

Physics of Fluids

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In the present study, the evolutionary multi-objective optimization is employed to design the optimum amplitude and wavelength of sinusoidal leading-edge tubercles for the NACA0012 (National Advisory Committee for Aeronautics) airfoil to improve its aerodynamic performance at Reynolds number of 5.0 × 104 than that of the NACA0012 smooth leading-edge or baseline airfoil. Here, the optimum tubercle is found to have an amplitude of 11.71% and a wavelength of 25% of the baseline airfoil chord, respectively. Through a combination of in-house water tunnel experiments and numerical simulations, it is additionally established that the optimized tubercle airfoil exhibits superior lift and reduced drag characteristics compared to the baseline airfoil, particularly in the post-stall high angle of attack regime. Furthermore, it is noticed that the optimized tubercle design enhances the gap between large separation regions or stall cells along the tubercle airfoil span during the post-stall regime. Consequently, a more pronounced attached flow regime is developed between the consecutive stall cells, contributing to the tubercle airfoil's improved aerodynamic characteristics compared to the baseline airfoil. Our investigations also revealed that the formation and arrangement of the stall cells on the tubercle airfoil span are associated with a biased wake mechanism similar to the one observed in the wake of side-by-side arranged circular cylinders.

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Section: Introductionmentioning

confidence: 99%

On the investigation of the aerodynamics performance and associated flow physics of the optimized tubercle airfoil

Pinapatruni,

Duddupudi,

Dash

et al. 2024

Physics of Fluids

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A comprehensive review of the application of bio-inspired tubercles on the horizontal axis wind turbine blade

Roy

Das

Biswas

2022

Int. J. Environ. Sci. Technol.

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Modeling of the compartmentalization effect induced by leading-edge tubercles

et al. 2022

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As a passive flow control technique, the use of leading-edge tubercles inspired by humpback whale flippers has attracted much interest. It is believed that one of the flow control mechanisms of leading-edge tubercles is compartmentalization, which is similar to the way in which wing fences act. However, to date, there has been no direct evidence for this belief. In view of this, the present work aims to verify and quantitatively describe the compartmentalization effect induced by leading-edge tubercles. Numerical simulation is performed to investigate the flow structures on a wavy airfoil with leading-edge tubercles, and the results reveal the presence of typical biperiodic flow patterns when a critical angle of attack is exceeded. Based on the flow characteristics of the wavy airfoil, special fences paired in a diverging configuration are designed and positioned on the baseline airfoil. A modeling method is developed to determine the main parameters of the fence configurations. It is found that the fenced airfoils designed using this method are able to reproduce the typical flow characteristics of the wavy airfoil under different inflow conditions. The spanwise distributions of the sectional airfoil performance under flow control by leading-edge tubercles and by the specially designed fences are very similar. This work provides strong evidence to confirm the compartmentalization mechanism of action of leading-edge tubercles, as well as developing a quantitative modeling method, both of which are important for fully understanding the underlying mechanism and guiding further optimization of this passive flow control technique.

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An empirically-based model for the lift coefficients of twisted airfoils with leading-edge tubercles

Cited by 8 publications

References 21 publications

On the investigation of the aerodynamics performance and associated flow physics of the optimized tubercle airfoil

On the investigation of the aerodynamics performance and associated flow physics of the optimized tubercle airfoil

A comprehensive review of the application of bio-inspired tubercles on the horizontal axis wind turbine blade

Modeling of the compartmentalization effect induced by leading-edge tubercles

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