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Updated: May 30, 2025
09:17
Experimental Investigation of the Flow Structure over a Delta Wing Via Flow Visualization Methods
Published on: April 23, 2018
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Highly deformable flapping membrane wings suppress the leading edge vortex in hover to perform better
Alexander Gehrke1, Karen Mulleners1
1École polytechnique fédérale de Lausanne, School of Engineering, Institute of Mechanical Engineering, Unsteady Flow Diagnostics Laboratory, Lausanne 1015, Switzerland.
Summary
Highly flexible wings, like those of bats, may not form leading edge vortices. Instead, they achieve enhanced lift and energy efficiency through a bound shear layer, differing from insect flight mechanisms.
Area of Science:
- * Fluid dynamics and bio-inspired engineering.
- * Aerodynamics of flapping flight in insects and bats.
Background:
- * Insects utilize leading edge vortices (LEVs) for enhanced lift during flapping flight.
- * Insect wings are rigid membranes, unlike the highly deformable wings of bats.
Purpose of the Study:
- * To investigate the role of LEVs in highly deformable membrane wings.
- * To understand how wing flexibility affects vortex formation and aerodynamic performance.
- * To explore alternative lift generation mechanisms in flexible wings.
Main Methods:
- * Experimental study on deformable membrane wings under fluid dynamic loading.
- * Analysis of wing deformation, vorticity, and aerodynamic forces.
- * Scaling analyses and identification of flow state indicators (geometric angles).
Main Results:
- * Increased wing flexibility suppresses coherent leading edge vortex formation.
- * Optimal aeroelastic conditions show no LEV, but a bound shear layer.
- * Deformable wings achieve higher lift and energy efficiency than rigid wings.
Conclusions:
- * Flexible membrane wings can achieve efficient flight without LEVs.
- * A bound shear layer is a key mechanism for lift in deformable wings.
- * Findings may explain efficient hovering in small bats and inform robotic flight design.
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