Experimental investigation of fluctuating forces exerted on a cylindrical tube (Reynolds numbers from 3000 to 30 000)

In this paper, an experimental investigation of variations of the global lift coefficient as a function of the Reynolds number is discussed. The experimental unit was capable of measuring the lift coefficient at Reynolds numbers ranging from 3000 to 30 000. Since the intensity of the unsteady lift forces was of the order of few millinewtons, a sensor and signal‐conditioning circuit was specially designed for measurement. The velocity field and the flow turbulence rate were measured upstream from the cylinder using laser‐Doppler anemometry. Tube aspect ratio, blockage, and ends effects are discussed. The evolution of the Strouhal number was observed as the Reynolds number passed from 3000 to 30 000. When measured as a function of the Reynolds number, the global lift coefficient displayed considerable variation for Reynolds numbers between 3000 and 10 000.