Size effects on insect hovering aerodynamics: an integrated computational study

TLDR

Hovering is a remarkable phenomenon observed across all insect sizes, and understanding how size influences flapping‑wing aerodynamics is crucial for both MAV design and comparative morphologists. The study aims to investigate size effects on insect hovering aerodynamics using an integrated computational approach. The authors employ a biology‑inspired dynamic flight simulator that models realistic wing–body morphology, flapping‑wing and body kinematics, and solves the Navier–Stokes equations in‑house. Results from hawkmoth, honeybee, fruit fly, and thrips hovering flights across Reynolds numbers O(10⁴)–O(10¹) confirm the method’s feasibility and provide integrated insights into vortex dynamics, wake structures, and force production, highlighting its utility for MAV design.

Abstract

Hovering is a miracle of insects that is observed for all sizes of flying insects. Sizing effect in insect hovering on flapping-wing aerodynamics is of interest to both the micro-air-vehicle (MAV) community and also of importance to comparative morphologists. In this study, we present an integrated computational study of such size effects on insect hovering aerodynamics, which is performed using a biology-inspired dynamic flight simulator that integrates the modelling of realistic wing–body morphology, the modelling of flapping-wing and body kinematics and an in-house Navier–Stokes solver. Results of four typical insect hovering flights including a hawkmoth, a honeybee, a fruit fly and a thrips, over a wide range of Reynolds numbers from O(104) to O(101) are presented, which demonstrate the feasibility of the present integrated computational methods in quantitatively modelling and evaluating the unsteady aerodynamics in insect flapping flight. Our results based on realistically modelling of insect hovering therefore offer an integrated understanding of the near-field vortex dynamics, the far-field wake and downwash structures, and their correlation with the force production in terms of sizing and Reynolds number as well as wing kinematics. Our results not only give an integrated interpretation on the similarity and discrepancy of the near- and far-field vortex structures in insect hovering but also demonstrate that our methods can be an effective tool in the MAVs design.