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arXiv · 1109.5825

Spatio-temporal spectral analysis of a forced cylinder wake

Juan D'Adamo·Ramiro Godoy-Diana·José Eduardo Wesfreid
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Abstract

The wake of a circular cylinder performing rotary oscillations is studied using hydrodynamic tunnel experiments at $Re=100$. Two-dimensional particle image velocimetry on the mid-plane perpendicular to the axis of cylinder is used to characterize the spatial development of the flow and its stability properties. The lock-in phenomenon that determines the boundaries between regions of the forcing parameter space were the wake is globally unstable or convectively unstable is scrutinized using the experimental data. A novel method based on the analysis of power density spectra of the flow allows us to give a detailed description of the forced wake, shedding light on the energy distribution in the different frequency components and in particular on a cascade-like mechanism evidenced for a high amplitude of the forcing oscillation. In addition, a calculation of the drag from the velocity field is performed, allowing us to relate the resulting force on the body to the wake properties.

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Juan D'Adamo, Ramiro Godoy-Diana, José Eduardo Wesfreid. 2011-09-27. Spatio-temporal spectral analysis of a forced cylinder wake. https://doi.org/10.1103/physreve.84.056308

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