MEchanics GAthering –MEGA- Seminar: Talk 1 - Improving vertical-axis wind turbines with blade pitch control; Talk 2 - To swim fast or to go far: answers from 1-guilla, a bio-inspired undulatory robot
Event details
| Date | 09.11.2023 |
| Hour | 16:15 › 17:30 |
| Speaker | Daniel Fernex (UNFoLD, EPFL) Alexandros Anastasiadis (UNFoLD, BioRob, EPFL) |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
Talk 1: Improving vertical-axis wind turbines with blade pitch control
by Daniel Fernex
Abstract:
The large-scale implementation of vertical-axis wind turbines is limited by the turbines’ lower efficiency and shorter lifetime, rooted in the high unsteadiness of the flow and blade loading. We address these limitations with blade-pitch angle control to alter the flow separation and dynamic stall development. The control law, optimized with Bayesian optimization, reorients the blades to modify the flow and reduce the detrimental effects of dynamic stall. This actuation yields a high control authority over the flow and enables to achieve numerous objectives, such as an increase of the power production by 219% and a reduction of undesired transient load fluctuations.
Biography:
Daniel Fernex is a postdoctoral fellow in the Unsteady Flow Diagnostics Laboratory (UNFoLD) at EPFL. After a PhD at the Technical University of Braunschweig, Germany, he moved to Switzerland for a post-doc position at EPFL. Daniel's main focus is the improvement of vertical-axis wind turbines using blade pitch control. He implements and tests open and closed-loop control solutions to explore the potential of this actuation to manipulate the flow and achieve better performance.
Talk 2: To swim fast or to go far: answers from 1-guilla, a bio-inspired undulatory robot
by Alexandros Anastasiadis
Abstract:
Natural undulatory swimmers are observed to adapt their waveform kinematics when migrating or when swimming against strong currents. To characterise the effects of waveform kinematics on the swimming performance of undulatory swimmers, we designed a bio-inspired anguilliform robot. We measured the robot’s swimming speed, efficiency, in terms of the cost of transport, and body kinematics in free swimming experiments, for a broad range of kinematic parameters, including joint amplitude, body wavelength, and frequency. We find that speed, in terms of stride length, increases for increasing maximum tail angle, described by the newly proposed specific tail amplitude. Maximum stride length is reached for specific tail amplitudes around unity. Minimum cost of transport requires a lower specific tail amplitude and body undulations close to pure travelling waves. Live anguilliform swimmers display a range of specific tail amplitudes that match our robot’s efficient regime, suggesting similar mechanisms of efficient locomotion. The results improve our understanding of anguilliform swimming and provide guidelines for improved design of undulatory swimming robots.
Biography:
Alexandros is a Ph.D. student at EPFL. He has joined UNFoLD with Prof. Karen Mulleners and BioRob with prof. Auke Ijspeert, since July 2021. His research focuses on understanding the hydrodynamics of undulatory swimming with the use of robotics. Before joining EPFL, Alexandros obtained his diploma in mechanical engineering from the National Technical University of Athens in 2020.
by Daniel Fernex
Abstract:
The large-scale implementation of vertical-axis wind turbines is limited by the turbines’ lower efficiency and shorter lifetime, rooted in the high unsteadiness of the flow and blade loading. We address these limitations with blade-pitch angle control to alter the flow separation and dynamic stall development. The control law, optimized with Bayesian optimization, reorients the blades to modify the flow and reduce the detrimental effects of dynamic stall. This actuation yields a high control authority over the flow and enables to achieve numerous objectives, such as an increase of the power production by 219% and a reduction of undesired transient load fluctuations.
Biography:
Daniel Fernex is a postdoctoral fellow in the Unsteady Flow Diagnostics Laboratory (UNFoLD) at EPFL. After a PhD at the Technical University of Braunschweig, Germany, he moved to Switzerland for a post-doc position at EPFL. Daniel's main focus is the improvement of vertical-axis wind turbines using blade pitch control. He implements and tests open and closed-loop control solutions to explore the potential of this actuation to manipulate the flow and achieve better performance.
Talk 2: To swim fast or to go far: answers from 1-guilla, a bio-inspired undulatory robot
by Alexandros Anastasiadis
Abstract:
Natural undulatory swimmers are observed to adapt their waveform kinematics when migrating or when swimming against strong currents. To characterise the effects of waveform kinematics on the swimming performance of undulatory swimmers, we designed a bio-inspired anguilliform robot. We measured the robot’s swimming speed, efficiency, in terms of the cost of transport, and body kinematics in free swimming experiments, for a broad range of kinematic parameters, including joint amplitude, body wavelength, and frequency. We find that speed, in terms of stride length, increases for increasing maximum tail angle, described by the newly proposed specific tail amplitude. Maximum stride length is reached for specific tail amplitudes around unity. Minimum cost of transport requires a lower specific tail amplitude and body undulations close to pure travelling waves. Live anguilliform swimmers display a range of specific tail amplitudes that match our robot’s efficient regime, suggesting similar mechanisms of efficient locomotion. The results improve our understanding of anguilliform swimming and provide guidelines for improved design of undulatory swimming robots.
Biography:
Alexandros is a Ph.D. student at EPFL. He has joined UNFoLD with Prof. Karen Mulleners and BioRob with prof. Auke Ijspeert, since July 2021. His research focuses on understanding the hydrodynamics of undulatory swimming with the use of robotics. Before joining EPFL, Alexandros obtained his diploma in mechanical engineering from the National Technical University of Athens in 2020.
Practical information
- General public
- Free
Organizer
- MEGA.Seminar Organizing Committee