Fluctuating Forces Acting on Rectangular Cylinders in Uniform Flow : On Rectangular Cylinders with Fully Separated Flow

Abstract

Experimental investigations on the characteristics of the fluctuating forces acting on rectangular cylinders with fully separated flow were carried out at a Reynolds number of 5.5×10⁴. The widty-to-height ratio B/H of the section was varied from 0.3 to 2.5. Phase-averaged lift and drag forces were obtained in terms of phase-averaged surface pressure. The phase-averaged fluctuating lift and drag coefficients take the respective maximum values in the same tendency as that of the time-mean drag coefficients for the critical geometry of B/H=0.7. In addition, the torsional moment forces associated with the phenomenon of the vortex-induced flutter were discussed in detail based on the characteristic of the fluctuating pressure, whose frequency equals to the vortex shedding frequency, acting on the surfaces of the rectangular cylinders.