Calculation of the Vibration of an Elastically Mounted Cylinder Using Experimental Data From Forced Oscillation

Several methods for investigating the fluid-structure interaction of bodies vibrating due to vortex shedding are compared briefly. The advantage of employing a forced-displacement excitation method is asserted. This method has been adopted to measure the response of the fluid forces acting on an oscillating circular cylinder in crossflow. With the results of these measurements, and a calculation based on the assumption of sinusoidal motion, the vibrations of a freely oscillating cylinder are predicted in the lock-in range. It is shown that hysteresis effects, which are observed in experiments with elastically mounted cylinders of certain damping and mass ratios, are caused by the nonlinear relation between the fluid force and the amplitude of oscillation.