Publications related to Estimating the non-dimensional energy of vortex rings by modelling their roll-up

Reactive collision-free motion generation in joint space via dynamical systems and sampling-based MPC

Aude Billard, Nadia Barbara Figueroa Fernandez, Mikhail Koptev

Dynamical system (DS) based motion planning offers collision-free motion, with closed-loop reactivity thanks to their analytical expression. It ensures that obstacles are not penetrated by reshaping a nominal DS through matrix modulation, which is construc ...

Sage Publications Ltd2024

Strength and timing of primary and secondary vortices generated by a rotating plate

Karen Ann J Mulleners, Diego Francescangeli

Accurate predictions of how vortices grow, evolve, and separate from aerodynamic objects are desirable for various applications ranging from autonomous aerial vehicles to wind turbines. Here, we present an experimental characterisation of the formation pro ...

2023

Propagation of planar three-dimensional buoyant hydraulic fractures

Andreas Möri

Hydraulic fractures are driven by an internal fluid pressure exceeding the minimum compressive stress, propagating in a direction perpendicular to the latter. This class of tensile fractures has gained interest over the last fifty years due to the developm ...

EPFL2023

Mechanism balancing taxonomy

Simon Nessim Henein, Florent Cosandier, Hubert Pierre-Marie Benoît Schneegans

The balancing of mechanisms consists in distributing their moving masses, inertias, and elastic components in order to achieve key mechanical properties, such as the elimination of the shaking forces and moments exported onto their supporting structure or ...

2023

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

Lagrangian analysis of bio-inspired vortex ring formation

Karen Ann J Mulleners, Mrudhula Baskaran

Pulsatile jet propulsion is a highly energy-efficient swimming mode used by various species of aquatic animals that continues to inspire engineers of underwater vehicles. Here, we present a bio-inspired jet propulsor that combines the flexible hull of a je ...

2022

Growth, timing, & trajectory of vortices behind a rotating plate

Diego Francescangeli

The presence of aerodynamic vortices is widespread in nature. They can be found at small scales near the wing tip of flying insects or at bigger scale in the form of hurricanes, cyclones or even galaxies. They are identified as coherent regions of high vor ...

EPFL2022

Analytical Studies in Support of an Improved Approach to the Design of Acceleration-Sensitive Nonstructural Elements

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper summarizes a series of analytical studies that were conducted in connection with an improved approach for the design of acceleration-sensitive nonstructural elements. In the new approach, bracing to secure nonstructural elements to the structure ...

Applied Technology Council, Sponse2022

Scaling of the translational velocity of vortex rings behind conical objects

Karen Ann J Mulleners, Guillaume de Guyon-Crozier

Ring vortices are efficient at transporting fluid across long distances. They can be found in nature in various ways: they propel squids, inject blood in the heart, and entertain dolphins. These vortices are generally produced by ejecting a volume of fluid ...

2021

Evolution of the vorticity distribution in vortex rings

Guillaume de Guyon-Crozier

Vortex rings are very efficient at transporting fluid on long distances and can generate large forces, either thrust or drag. These abilities are influenced by the vorticity distribution within the vortex. Previous work on vortices produced by piston-cylin ...

EPFL2021