Related Experiment Video
Updated: Jun 2, 2025

A Simple Flight Mill for the Study of Tethered Flight in Insects
Published on: December 10, 2015
Hovering hawkmoths exploit unsteady circulation to produce aerodynamic force
Yun Liu1, Biao Li2, Deli Zhou2
1Department of Mechanical and Civil Engineering, Purdue University Northwest, Hammond, IN 46323, USA.
Abstract:
This study employs an integrated approach, combining three-dimensional flow visualization and two-dimensional flow measurement to investigate the underlying unsteady aerodynamic mechanisms of hovering hawkmoths. Using a single vortex ring model, three aerodynamic force components, such as aerodynamic force induced by unsteady circulation, vortex loop size variation and added mass, are estimated within a dimensionless time (normalized by one wing beat cycle) range of 0.418 < T* < 0.455, where both the vortex loop circulation and loop size data are available. The force analysis reveals that the unsteady circulation-induced aerodynamic force dominates the overall force production and contributes 67% of the total force while the vortex loop size variation and added mass effect-induced aerodynamic forces only count for 25% and 8%, respectively. These findings suggest the hawkmoth primarily relies on unsteady circulation to generate aerodynamic forces.
Related Concept Videos
Cohesion
On a...
Lift
Predator-Prey Interactions
Optimal Foraging
Steady, Laminar Flow in Circular Tubes
Absolute Motion Analysis- General Plane Motion
As the drone's propellers rotate, an upward force is generated that counteracts the force of gravity, enabling the drone to lift off from the ground. This initial movement of the drone is along a straight path, representing a form of translational motion. In this phase, every point on the...

