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Accueil du site > Évènements > Séminaires > Séminaires IRPHE > Archives IRPHE > 2017

Vendredi 24 Mars 2017/ IRPHE

publié le , mis à jour le

Séminaire exceptionnel IRPHE

Vortex-induced vibrations of a rotating sphere

Orateur : Kerry Hourigan
Dept. of Mechanical and Aerospace Engineering, Monash University, Melbourne, Australie

Abstract : Vortex-induced vibration (VIV) of a sphere represents one of the most generic fundamental fluid-structure interaction problems. Since vortex-induced vibration can lead to structural failure, numerous studies have focused on understanding the underlying principles of VIV and its suppression. This seminar presents results from an experimental investigation of the effect of imposed axial rotation on the dynamics of vortex-induced vibration of a sphere that is free to oscillate in the cross-flow direction, by employing simultaneous displacement and force measurements. The VIV response was investigated over a wide range of reduced velocities, 3 < U* < 18 , corresponding to a Reynolds number range of 5 000 < Re < 30 000, while the rotation ratio, defined as the ratio between the sphere surface and inflow speeds, was varied in increments over the range of 0 to 7.5. It is found that the vibration amplitude exhibits a typical inverted bell-shaped variation with reduced velocity, similar to the classic VIV response for a non-rotating sphere but without the higher reduced velocity response tail. The vibration amplitude decreases monotonically and gradually as the imposed transverse rotation rate is increased up to 6, beyond which the body vibration is significantly reduced. The synchronisation regime also becomes narrower as the rotation rate is increased, with the peak saturation amplitude observed at progressively lower reduced velocities.

Date et lieu : vendredi 24 mars 2017à 11h00, salle de séminaires IRPHE