An Experimental Study on Vortex-Induced Vibrations of a Cylinder in Shear-Thinning Flow *

Traditional vortex-induced vibration (VIV) experiments subject a flexible or flexibly-mounted cylinder to Newtonian flow. In this work, we present experimental results on VIV of a one-degree-of-freedom cylinder placed in shear-thinning flows. These experiments were conducted in a water channel using a cylinder with a diameter of 2 mm. In each series of experiments, we kept the characteristic Reynolds number, defined based on the characteristic viscosity using the Carreau model, constant and varied the reduced velocity. For experiments at constant characteristic Reynolds numbers, we observed a lock-in region in a reduced velocity range of approximately 6 to 9 with a maximum amplitude of oscillations of approximately 0.3D. The amplitude of oscillations and the width of the lock-in region decreased with decreasing characteristic Reynolds number and at characteristic Reynolds numbers lower than 18, VIV was completely suppressed.