On the role of thickness ratio and location of axis of rotation in the flat plate motions

Y. Jin, S. Ji, B. Liu, L. P. Chamorro

Research output: Contribution to journalArticle

Abstract

Wind tunnel experiments were performed to characterize the flow-induced rotations and pitching of various flat plates as a function of the thickness ratio and the location of the axis of rotation. High-resolution telemetry, laser tachometer, and hotwire were used to get time series of the plates motions and the signature of the wake flow at a specific location. Results show that small axis offset can induce high-order modes in the plate rotation due to torque unbalance, and can trigger self-initiated pitching. The spectral decomposition of the flow velocity in the plate wake reveals the existence of a dominating high-frequency mode that corresponds to a static-like vortex shedding occurring at the maximum plate pitch. The associated characteristic length scale is the projected width at maximum pitching angle. The increase of the plate thickness ratio implies lower angular velocity in rotation cases. A simple model based on aerodynamic forces is used to explain the linear relation between pitching frequency and wind speed, the pitching frequency increase with axis offset, and the onset of pitching.

Original languageEnglish (US)
Pages (from-to)127-137
Number of pages11
JournalJournal of Fluids and Structures
Volume64
DOIs
StatePublished - Jul 1 2016

Keywords

  • Flat plate
  • Plate oscillation
  • Rotation
  • Turbulence

ASJC Scopus subject areas

  • Mechanical Engineering

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