Titre :

Effect of time-varying freestream on performance and vortex dynamics of forward and reversed pitching airfoils

Auteur(s) :

Shi, Lei [Auteur]
JiangSu University
Laboratoire de Mécanique des Fluides de Lille - Kampé de Fériet [LMFL]
Wang, Yefang [Auteur]
JiangSu University
Bayeul-Laine, Annie-Claude [Auteur]
Laboratoire de Mécanique des Fluides de Lille - Kampé de Fériet [LMFL]
Coutier-Delgosha, Olivier [Auteur]
Department of Aerospace and Ocean Engineering [Blackburg]
Laboratoire de Mécanique des Fluides de Lille - Kampé de Fériet [LMFL]

Titre de la revue :

Journal of Fluids and Structures

Pagination :

103508

Éditeur :

Elsevier

Date de publication :

2022-04

ISSN :

0889-9746

Mot(s)-clé(s) en anglais :

Flapping foil
Energy extraction
Renewable energy
Non-sinusoidal trajectory
CFD

Discipline(s) HAL :

Sciences de l'ingénieur [physics]

Résumé en anglais : [en]

The goal of the present work deals with the influence of the oscillating freestream on the global performance, transition and vortex dynamics of forward and reversed airfoils. Three important parameters, involving the ...
Lire la suite >The goal of the present work deals with the influence of the oscillating freestream on the global performance, transition and vortex dynamics of forward and reversed airfoils. Three important parameters, involving the phase lag, oscillating amplitude and mean reduced frequency, are analyzed systematically. The primary results show that both the phase lag and oscillating amplitude have great impact on the transition and flow structures, depending on the instantaneous freestream Reynolds number. The reversed airfoil is more prone to being affected by these parameters, characterized by the earlier flow separation near the sharp leading edge and the more complex vortex shedding, compared with that over the forward airfoil. It shows that increasing the oscillating amplitude can improve the mean performance, but it decreases with the increase of the mean reduced frequency. Additionally, it is observed that there is a second transition on both two sides near the trailing edge of the reversed airfoil, which becomes weak when the instantaneous freestream Reynolds number is relatively low. Afterwards, the time-averaged performance of the reversed airfoil is better than forward airfoil at low reduced frequency, but it deteriorates dramatically with the increase of the reduced frequency. Furthermore, the transition and vortex evolution are delayed as the reduced frequency increases, and the delayed flow structures can be inferred from the velocity profiles in the wake region. Moreover, it can be seen that the velocity profile has a transition from the drag-indicative to thrust-indicative type when the reduced frequency increases, and the velocity variation in the vertical direction is more evident for the reversed airfoil due to the massive flow separation.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Collections :

• Laboratoire de Mécanique des Fluides de Lille Kampé de Fériet (LMFL) - UMR 9014

Source :

Harvested from HAL