Effects of Oscillating Incoming Flow on Flow-Induced Forces on a Yawed Circular Cylinder

Published

August 31, 2011

Author(s)

Dong Hun Yeo, Nicholas P. Jones

Abstract

A detached eddy simulation (DES) study was conducted on oscillating flow around a yawed circular cylinder at Re = 1.4×105 to investigate how the oscillating frequency of incoming flow affects the characteristics of flow around the cylinder and the resulting induced forces. The reduced frequencies of incoming flow employed in this study were 1) fro = 0.000 (uni-form incoming flow without oscillation, 2) fro = 0.033 (a low frequency observed in the forces that are generated under uniform incoming flow), and 3) fro = 0.200 (a high frequency as-sociated with the forces under the uniform flow). Results showed that development of flow around a yawed cylinder is highly affected by the oscillation frequency of the incoming flow, and that the modified patterns thus developed in the wake exert a considerable influence on the characteristics of the forces on the cylinder. When the incoming flow oscillates at low frequency (fro = 0.033), the oscillation maintains the forces developing along the cylinder axis that are also seen in the case of uniform incoming flow and even increases the magnitude of the forces, while preserving the low frequency. However, the oscillating flow at the frequency of Kármán vortex shedding (fro = 0.200) breaks up the three-dimensionality of the flow and reorganizes the flow structures by increasing their spatial correlation over the cylinder length. The associated forces have the characteristics of Kármán vortex-induced forces over the entire length of the cylinder. This investigation contributed to understanding of a mechanism of force generation on an oscillating cable. When an oblique cable oscillates at the low frequency generated by oblique wind-induced aerodynamic forces, the forces play an important role in initiating and increas-ing the vibration at the low frequency. However, when an oblique cable oscillates at a fre-quency as high as that of Kármán vortex shedding, the three-dimensional characteristics that develop along the cable axis a

Proceedings Title

13th International Conference on Wind Engineering

Conference Dates

July 11-15, 2011

Conference Location

Amsterdam

Pub Type

Conferences

Keywords

oscillating incomin gflow, yawed circular cylinder, cable vibration, aerodynamic effects

Citation

, D. and Jones, N. (2011), Effects of Oscillating Incoming Flow on Flow-Induced Forces on a Yawed Circular Cylinder, 13th International Conference on Wind Engineering, Amsterdam, -1 (Accessed March 13, 2025)