Effect of vibration on the aerodynamic behavior of a 5:1 rectangular cylinder

Synchronized surface pressure measurements and forced motion techniques are performed in a wind tunnel to investigate the aerodynamic characteristics of an oscillatory rectangular cylinder with a 5:1 benchmark section. The effects of the vertical and torsional vibration amplitude and the Reynolds number (Re) on the streamwise surface pressure are studied. The results show that the impact of vertical motion on the streamwise correlation of surface pressure is relatively smaller than that of torsional motion. It is also found that the effect of input energy from the forced motion and vortex shedding on the surface pressure does not remain constant along streamwise direction versus vibration amplitude. A method of estimating the flow structure around an oscillatory cylinder is proposed in terms of phase difference between the separation point and downstream pressure taps at vortex-shedding frequency, as well as the standard deviation, correlation coefficient and pressure contours. The Proper Orthogonal Decomposition (POD) technique is also introduced to lead to a better physical understanding and analyzing three-dimensional (3D) features of the pressure field structure around an oscillatory cylinder. Finally, the non-Gaussian features of the fluctuating surface pressure versus the vibration amplitudes are also investigated. This paper is intended to be a supplement to the 5:1 benchmark framework.