Scaling laws for the sound generation of bio-inspired flapping wings

TL;DR

This paper develops and validates scaling laws for predicting the sound generated by bio-inspired flapping wings during hovering, aiding the design of quieter micro-aerial vehicles.

Contribution

It introduces new scaling laws based on potential flow theory and acoustic analogy, validated through numerical simulations, to predict sound emission of flapping wings.

Findings

Scaling laws accurately predict sound generation.

Predictions agree well with numerical simulations.

Useful for designing quieter MAVs.

Abstract

Bio-inspired flapping wings have been extensively studied for their remarkable aerodynamic performance. Recently, their noise emission has attracted growing interest, but a careful analysis of scaling laws for their sound generation is missing. This work presents scaling laws for the sound generation of bio-inspired flapping wings during hovering flight based on the potential flow theory and Ffowcs Williams-Hawkings acoustic analogy. Direct numerical simulations considering a range of parameters including the Reynolds number, Mach number and wing kinematics confirms that the proposed scaling laws capture the major physics involved and their predictions agree well with the numerical results. The scaling laws can be used as a powerful tool for engineers in the design of micro-aerial vehicles considering both aerodynamics and acoustics performances simultaneously.