Coupled thrust and vorticity dynamics during vortex ring state

Savas, O., Green, R.B. and Caradonna, F.X. (2009) Coupled thrust and vorticity dynamics during vortex ring state. Journal of the American Helicopter Society, 54, 022001. (doi: 10.4050/JAHS.54.022001)

Abstract

This paper focuses on the vortex ring state (VRS) that is observed in the flow around a rotor during rapid descent. In VRS, the vortex filaments trailed off the blades coalesce around the rotor disk. This vortex ring detaches into the wake periodically, causing extreme oscillations in thrust, with periods on the order of several tens of rotor revolutions. The phase relation between the thrust cycle and vorticity distribution at the rotor disk is discussed. Maxima of the VRS thrust oscillations correlate well with the maxima of circulation, enstrophy, and minima of enstrophy dispersion radius observed in the vicinity of the rotor disk.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Green, Dr Richard
• Authors: Savas, O., Green, R.B., and Caradonna, F.X.
• Subjects: T Technology > TJ Mechanical engineering and machinery; Q Science > QC Physics
• College/School: College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity
• Journal Name: Journal of the American Helicopter Society
• Publisher: American Helicopter Society
• ISSN: 0002-8711