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Bio-inspired rotor designs: enhancing thrust, energy efficiency, and noise reduction
Andrea Rapisarda1,2, Luca Sangiuliano2, Luca D'Alessandro2
1Department of Civil, Environmental and Mechanical Engineering, University of Trento, Laboratory for Bioinspired, Bionic, Nano, Meta, Materials & Mechanics, Via Mesiano, 77, Trento 38123, Italy.
Bioinspiration & Biomimetics
|August 2, 2025
Summary
Bio-inspired trailing-edge serrations on fan blades significantly reduce noise pollution by up to 5 decibels. This passive strategy enhances aerodynamic stability without compromising efficiency, offering a promising solution for quieter mechanical ventilation systems.
Area of Science:
- Acoustics and Fluid Dynamics
- Bio-inspired Engineering
- Environmental Science
Background:
- Urban noise pollution from mechanical ventilation systems is a growing environmental concern.
- Fan noise, a major contributor, includes disruptive tonal and broadband components.
- Current noise reduction strategies often face limitations.
Purpose of the Study:
- To investigate trailing-edge serrations as a passive noise-reduction method for fan blades, inspired by owl flight.
- To analyze the impact of serration geometry on acoustic performance and aerodynamics.
- To develop a framework for designing low-noise fan systems.
Main Methods:
- Hybrid numerical approach coupling Large Eddy Simulations (LES) with acoustic analogy models.
- Sensitivity analysis of serration parameters (number, sawtooth ratio).
- Experimental validation across varying rotational speeds.
Main Results:
- Trailing-edge serrations achieved noise reductions of up to 5 decibels.
- Aerodynamic efficiency, thrust, and drag remained largely unaffected.
- Serrations improved spanwise flow coherence and turbulence stabilization.
Conclusions:
- Bio-inspired serrations offer an effective passive noise control strategy for fans.
- Geometric parameter optimization is key to maximizing noise reduction.
- This approach provides a foundation for developing quieter ventilation systems.
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