Investigating Wake Structures in Flow Past Oscillating Cylinder Using Proper Orthogonal Decomposition

TL;DR

This study uses Proper Orthogonal Decomposition to analyze unsteady wake dynamics in flow past an oscillating cylinder, exploring effects of various parameters on vortex shedding and flow behavior.

Contribution

It introduces a systematic analysis of wake structures in oscillating cylinder flow using POD, including high amplitude and wavelength regimes previously unexplored.

Findings

Flow is highly dissipative at low Reynolds numbers.

Frequency ratio influences vortex shedding synchronization.

High amplitude and wavelength effects on wake dynamics are characterized.

Abstract

The present study investigates unsteady wake dynamics in flow past oscillating cylinder. Two-dimensional computational study is carried out for flow past sinusoidally oscillating cylinder. Operating parameters like Reynolds number, forcing frequency, amplitude and wavelength are systematically varied and their effect on wake dynamics is investigated. Lift and drag coefficients are plotted with cylinder position to characterize the flow. Further, flow field is investigated using Proper Orthogonal Decomposition (POD). Time-resolved vorticity contours are obtained. These results are then processed using POD algorithm. POD mode shapes and Power Spectral Density (PSD) plots are obtained for each case. Wake dynamics is analyzed using POD results. Flow response to cylinder oscillations is characterized by the POD mode shape and dominant frequency peaks in PSD plots. It is observed that flow is too dissipative at lower values of Reynolds number. Further, effect of frequency ratio is observed in achieving synchronized vortex shedding. High amplitude and large wavelength regime, which remained unexplored in previous research is also investigated.