Vortex shedding and resistance in harmonic flow about smooth and rough circular cylinders at high Reynolds numbers

摘要

This report presents the results on an extensive experimental investigation of the in-line and transverse forces acting on smooth and rough circular cylinders placed in oscillatory water flow at Reynolds numbers up to 700,000, Keulegan-Carpenter numbers up to 150, and relative roughnesses from 0.002 to 0.02. The drag and inertia coefficients have been determined through the use of the Fourier analysis and the least-squares method. The transverse force (lift) has been analyzed in terms of its maximum, semi-peak-to-peak, and root-mean-square values. In addition, the frequency of vortex shedding and the Strouhal number have been determined