Wavelet Analysis of VIV Characteristics of Circular Cylinders Under Forced Oscillation

This research considers VIV characteristics of underwater tubing structures such as marine risers, from results of a forced oscillation experiment. The rigid circular cylinder models are used which have draft of 80 cm and 60cm and diameter of 5 or 8 cm are used for the experiment. One or two cylinders are arranged, and then the distance of two cylinders is changed in order to investigate influence of the interval ratio between two cylinders to VIV behaviors. The models are set as cantilever which bend in the cross-flow direction due to VIV, and this rolling serves as VIV. This paper describes results of VIV characteristics with the wavelet transform analysis. From the model experiment, relationship between the orbit pattern of vibration of the model cylinder and a contour pattern of the wavelet is considered. As a result, effectiveness of the wavelet analysis in order to understand VIV detail is given.Copyright © 2009 by ASME