Abstract
The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE) effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD) study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c), the wavelength (0.25c) is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.
Highlights
Biomimetics is the art of studying and applying nature inspired designs in the field of engineering
The Cl vs Angle of Attack (AoA) and Cd vs AoA results are as shown in Figs 9 and 10
The performance of an airfoil is measured by its L/D, Tubercle Leading Edge (TLE) airfoil clearly outperforms the clean airfoil as shown in Table 6 and Fig 23 [Data is provided in S1–S4 Data]
Summary
Biomimetics is the art of studying and applying nature inspired designs in the field of engineering. Few of the previous parametric studies conducted considering TLE are reported below Aftab et al, [7]. Chen et al, [15] investigated the effect of the tubercles on the performance of a moderately swept delta wing. Chen et al, [16] further investigated the effect of tubercles on a highly swept delta wing. Gawad [20, 21] conducted CFD study on NACA 0012 implementing spherical TLE and reported that, it performed better compared to the sinusoidal TLE. A parametric study is carried out between the two designs by varying the tubercle amplitude, inorder to determine which design is more suitable for NACA 4415 airfoil. Experimental testing in wind tunnel is carried out, based on the best tubercle design
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