Forces on Cylinders and Spheres in a Sinusoidally Oscillating Fluid

Abstract

The in-line and transverse forces acting on circular cylinders and the in-line force acting on spheres immersed in a harmonically oscillating fluid in a U-shaped vertical tunnel have been measured. The drag, inertia, and the transverse force (lift) coefficients have been determined through the use of a Fourier analysis and found to depend on a period parameter. The results have shown that the transverse force on cylinders is as large as the in-line force and alternates at frequencies ranging from one to four times the driving frequency of the fluid within the range of subcritical Reynolds numbers encountered in the investigation.