Fluctuating Forces Acting on Two Circular Cylinders in Tandem Arrangement : Part2, Phase Relations Between Fluctuating Forces

Abstract

Phase-averaged lift and drag forces acting on two circular cylinders of the same diameter in tandem arrangement were studied experimentally. The phase averages were made in terms of the vortex-shedding frequency. Phase relationship between the lift forces of two circular cylinders was presented and discussed. The phase of vortex shedding from the downstream cylinder was dependent on that from the upstream cylinder. The phase of lift force acting on the downstream cylinder was determined by the arrival of vortices shed from the upstream cylinder when the distance between the two cylinders was four to ten times the cylinder diameter. The phase difference between lift forces acting on two cylinders was found to be proportional to the distance between their centres.