Wind turbines can lose a lot of power when the airflow separates from the blade surface, a problem called “stall.” To solve this, engineers looked to nature. The fins of humpback whales have special bumps on their front edge. A Leading Edge Tubercle on a Wind Turbine Blade copies this amazing design. These bumps change the airflow, helping the blade resist stall and work better in a wider range of wind speeds. This project uses a CFD simulation to study the effect of these tubercles, based on the high-impact reference paper published in the top journal, Energy Conversion and Management [1].

• Reference [1]: Joseph, Jeena, and A. Sathyabhama. “Leading edge tubercle on wind turbine blade to mitigate problems of stall, hysteresis, and laminar separation bubble.” Energy Conversion and Management255 (2022): 115337.

Figure 1:  Comparison of a standard baseline blade (BB) and a blade with leading edge tubercles [1].

Simulation Process: Modeling the Humpback Whale-Inspired Airfoil

To begin our Leading Edge Tubercle fluent simulation, we first had to create the complex, wavy geometry of the blade’s leading edge. We then placed this blade inside a very large computational domain. This large area is needed to accurately capture the wake, which is the disturbed air that forms behind the blade. The entire domain was filled with a very fine mesh of 4,031,516 cells to ensure the results would be highly accurate.

Next, we set up the physics in ANSYS Fluent. The k-omega SST turbulence model was chosen. This model is perfect for this type of simulation because it is very good at predicting flow both very close to the blade’s surface and in the wake far downstream. In the simulation, air approaches the Leading Edge Tubercle airfoil at a positive angle of attack, which is a challenging condition where stall often happens.

Post-Processing: How Tubercles Control Flow and Prevent Stall

A detailed analysis of the simulation results reveals exactly how the whale-inspired bumps improve the blade’s performance. The velocity streamlines show that the tubercles act as flow control devices. In the valleys between the bumps, they create small, stable, rotating tunnels of air called vortices. These vortices pull high-energy air from the main flow down onto the blade’s surface. This process “energizes” the boundary layer, giving the air the strength to stay “stuck” to the blade instead of separating. The pressure field confirms this, showing areas of low pressure from -125.6 Pa in the valleys, which is the signature of these helpful vortices at work.

Figure 2: Velocity and pressure fields around the Leading Edge Tubercle blade, showing its aerodynamic effect.

Furthermore, this controlled airflow directly leads to better performance and stall prevention. By keeping the flow attached, the blade can generate more consistent lift and less drag, especially at high angles of attack. The wake behind the blade, shown by the blue colors in the velocity plot, has lower speeds of about 2-4 m/s. This indicates a smaller, more organized wake compared to a standard blade, which is direct proof of reduced energy loss and drag. The most significant finding of this Leading Edge Tubercle CFD analysis is that these simple bumps create a powerful aerodynamic mechanism. They prevent catastrophic stall, allowing the wind turbine to operate more efficiently and reliably, ultimately capturing more energy from the wind.