CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge

Area of Science:

• Fluid Dynamics
• Aerodynamics
• Bio-inspired Engineering

Background:

• Humpback whale tubercles are known for enhancing aerodynamic performance.
• Tubercle Leading Edge (TLE) technology effectively reduces flow separation and delays stall, particularly at low Reynolds numbers.

Purpose of the Study:

• To computationally investigate the aerodynamic effects of two Tubercle Leading Edge (TLE) shapes on a NACA 4415 airfoil.
• To compare the performance of sinusoidal and spherical TLE designs at a Reynolds number of 120,000.
• To validate findings with experimental data at a Reynolds number of 200,000.

Main Methods:

• Computational Fluid Dynamics (CFD) simulations using a structured mesh and the Transition SST turbulence model.
• Parametric study of spherical TLEs with varying amplitudes (0.025c, 0.05c, 0.075c) at a fixed wavelength (0.25c).
• Experimental validation of spherical TLE performance on a NACA 4415 airfoil.

Main Results:

• Spherical TLEs demonstrated superior aerodynamic performance compared to sinusoidal TLEs on the NACA 4415 airfoil.
• CFD results indicated significant flow separation reduction and stall delay with spherical tubercle designs.
• Experimental results at a higher Reynolds number corroborated the performance enhancement provided by spherical TLEs over a clean airfoil.

Conclusions:

• Spherical tubercle designs are more effective than sinusoidal designs for improving airfoil aerodynamics at low Reynolds numbers.
• TLEs, particularly spherical ones, offer a viable strategy for enhancing aerodynamic efficiency in various flow regimes.
• The study validates the efficacy of bio-inspired tubercle designs through both computational and experimental approaches.