Publications associées à Vol des insectes

Wing and tail morphing in birds and drones

To aid humans in civilian tasks, future drones will have to operate in large cities that abound with difficult flight conditions such as confined spaces, obstacles, and turbulent air. Such drones must cruise efficiently to cover vast distances fast and als ...

EPFL2023

The effects of kinematics, flexibility, and planform on the vortex formation and aerodynamic performance of flapping wing flight

Alexander Gehrke

In this thesis, the aerodynamic challenges in flapping wing flight are addressed. In particular, the effects of different wing kinematics, flexibilities, and planforms on the the leading edge vortex development and aerodynamic performance are investigated. ...

EPFL2023

Fluid-structure interactions of bristled wings: the trade-off between weight and drag

Pedro Miguel Nunes Pereira de Almeida Reis, Matteo Pezzulla, Yuexia Luna Lin

The smallest flying insects often have bristled wings resembling feathers or combs. We combined experiments and three-dimensional numerical simulations to investigate the trade-off between wing weight and drag generation. In experiments of bristled strips, ...

Royal Soc2023

Vortex shedding from a composite hydrofoil: Experimental evidence of a novel "partial lock-in"

Mohamed Farhat, Thomas Antoine Nicolas Berger, Qin Wu, Yunqing Liu

Lock-in is of great importance in many engineering applications due to its practical implications for structural safety. The influence of composite bend-twist coupling on the wake dynamics and vortex-induced vibration around a carbon fiber composite hydrof ...

Aip Publishing2023

Not gone with the wind: Active microscale flight with highly porous bristled wings

Pedro Miguel Nunes Pereira de Almeida Reis, Yuexia Luna Lin

The finesse of sub-millimeter insect flight with comb-like bristled wings raises intriguing questions, not only on fluid-structure interactions (FSI) but also on the mechanical behavior of the underlying, highly porous structures. Farisenkov et al. charact ...

ELSEVIER2022

To tread or not to tread: comparison between water treading and conventional flapping wing kinematics

Karen Ann J Mulleners, Alexander Gehrke, Swathi Badala Krishna

Hovering insects are limited by their physiology and need to rotate their wings at the end of each back-and-forth motion to keep the wing's leading edge ahead of its trailing edge. The wing rotation at the end of each half-stroke pushes the leading edge vo ...

IOP Publishing Ltd2022

Observing the Central Arctic Atmosphere and Surface with University of Colorado uncrewed aircraft systems

Julia Schmale, Radiance Flore Aurore Calmer

Over a five-month time window between March and July 2020, scientists deployed two small uncrewed aircraft systems (sUAS) to the central Arctic Ocean as part of legs three and four of the MOSAiC expedition. These sUAS were flown to measure the thermodynami ...

NATURE PORTFOLIO2022

Aeroelastic characterisation of a bio-inspired flapping membrane wing

Karen Ann J Mulleners, Alexander Gehrke, Esra Uksul, Jules Ange Philippe Richeux

Natural fliers like bats exploit the complex fluid-structure interaction between their flexible membrane wings and the air with great ease. Yet, replicating and scaling the balance between the structural and fluid-dynamical parameters of unsteady membrane ...

IOP Publishing Ltd2022

Phenomenology and scaling of optimal flapping wing kinematics

Karen Ann J Mulleners, Alexander Gehrke

Biological flapping wing fliers operate efficiently and robustly in a wide range of flight conditions and are a great source of inspiration to engineers. The unsteady aerodynamics of flapping wing flight are dominated by large-scale vortical structures tha ...

IOP PUBLISHING LTD2021

The dynamics and timescales of static stall

Karen Ann J Mulleners, Sébastien Le Fouest, Julien Dominique Claude Deparday

Airfoil stall plays a central role in the design of safe and efficient lifting surfaces. We typically distinguish between static and dynamic stall based on the unsteady rate of change of an airfoil’s angle of attack. Despite the somewhat misleading denotat ...

2021

Bioinspired wing and tail morphing extends drone flight capabilities

Dario Floreano, Stefano Mintchev, Enrico Ajanic, Flavio Noca, Mir Alikhan Bin Mohammad Feroskhan

The aerodynamic designs of winged drones are optimized for specific flight regimes. Large lifting surfaces provide maneuverability and agility but result in larger power consumption, and thus lower range, when flying fast compared with small lifting surfac ...

2020

Stall Delay and Leading-Edge Suction for a Pitching Airfoil with Trailing-Edge Flap

Karen Ann J Mulleners, Julien Dominique Claude Deparday, Guosheng He

The flow around a pitching NACA0015 airfoil with an oscillating trailing-edge flap is experimentally investigated to characterize the influence of the flap kinematics on the development of dynamic stall. We specifically focus on the timing of the stall dev ...

2020

Physical Mechanism and Flow Control of Tip Vortex Cavitation

Ali Amini

Occurrence of cavitation in hydraulic machines is a challenging issue because it is often accompanied with loss of efficiency, noise emissions, vibrations, and erosion damages. Tip vortices, in particular, are an ideal site for the development of cavitatio ...

EPFL2020

Suppressing tip vortex cavitation by winglets

Mohamed Farhat, Ali Amini, Martino Reclari

Despite the numerous remedies prescribed so far, tip vortex cavitation (TVC) remains a major issue in design and operation of diverse applications. In this paper, we experimentally investigate the effectiveness of winglets in suppressing TVC. An elliptical ...

SPRINGER2019

The role of optic flow pooling in insect flight control in cluttered environments

Dario Floreano, Julien Jean Denis Nicolas Lecoeur, Emily Baird

Flight through cluttered environments, such as forests, poses great challenges for animals and machines alike because even small changes in flight path may lead to collisions with nearby obstacles. When flying along narrow corridors, insects use the magnit ...

Nature Research2019

Insect-Inspired Visual Perception for Flight Control and Collision Avoidance

Julien Jean Denis Nicolas Lecoeur

Flying robots are increasingly used for tasks such as aerial mapping, fast exploration, video footage and monitoring of buildings. Autonomous flight at low altitude in cluttered and unknown environments is an active research topic because it poses challen ...

EPFL2019

Bioinspired dual-stiffness origami

Dario Floreano, Stefano Mintchev, Jun Shintake

Origami manufacturing has led to considerable advances in the field of foldable structures with innovative applications in robotics, aerospace, and metamaterials. However, existing origami are either load-bearing structures that are prone to tear and fail ...

2018

Critical evolution of leading edge suction during dynamic stall

Karen Ann J Mulleners, Julien Dominique Claude Deparday

Dynamic stall dominates the aerodynamic performance, the robustness, and the wake dynamics of vertical axis wind turbines. To better assess the dynamic stall onset and its associated unsteady effects, this paper analyzes experimentally the evolution of the ...

IOP PUBLISHING LTD2018

Imaging neural activity in the ventral nerve cord of behaving adult Drosophila

Michaël Unser, Pavan P Ramdya, Chin-Lin Chen, Florian Aymanns, Denis Fortun, Laura Joan Hermans

To understand neural circuits that control limbs, one must measure their activity during behavior. Until now this goal has been challenging, because limb premotor and motor circuits have been largely inaccessible for large-scale recordings in intact, movin ...

Nature Research2018

Performance enhancement of downwind sails due to leading edge flapping: A wind tunnel investigation

Julien Dominique Claude Deparday

This work presents a wind tunnel experimental study on the effect of the leading edge flapping on the aerodynamic performance of a spinnaker. Four J80-class spinnaker models, combining two different assembling structures (panel layout) and two different sa ...

PERGAMON-ELSEVIER SCIENCE LTD2018