Vortex-induced vibration of a flexible rectangular cylinder: Experimental investigation and comparative study of theoretical models

Abstract

The vortex-induced vibration (VIV) of slender flexible structures is usually estimated based on two-dimensional aerodynamic parameters determined by sectional model wind tunnel tests. Before converting such test results into a prototype flexible structure, many complicated factors, such as the spanwise correlation of aerodynamic force and vibration mode shape, should be considered. In this study, wind tunnel tests of a 5:1 rectangular taut strip model and its sectional model with the same geometry were first conducted to analyze the relationship between the VIV amplitude of the flexible structure and sectional model. The results showed that the taut strip model sustained an approximately 15% higher VIV amplitude than the sectional model, indicating that the VIV amplitude could be underestimated if the sectional model test results were directly used. Next, based on the identified spanwise correlation function of the 5:1 rectangular cylinder, several existing VIV response estimation approaches based on Scanlan's semi-empirical vortex-induced force (VIF) model were examined and compared. Finally, an improved approach was proposed by which the correlation coefficients based on the partial spanwise correlation theory could be approximated with more comprehensive consideration of the spanwise correlation, allowing for a more accurate evaluation of the VIV amplitude for flexible structures.