Instability behaviors of a cylinder array under both increasing and decreasing flow velocities

This study aimed to investigate the effects of increasing and decreasing crossflow velocities on the fluid-elastic instability behaviors of cylinder arrays. The responses of an elastically mounted cylinder in a rigid normal square cylinder array in a water tunnel subjected to crossflow were tested. The responses were simultaneously obtained from both in-line and transverse vibrations. Results show that the responses under increasing freestream velocity differ from those under decreasing freestream velocity. Under decreasing freestream velocity, fluid-elastic instability was accompanied by nonlinear hysteresis, and the cylinder exhibiting this instability can remain in this state for a certain range of flow velocities. Added mass coefficients were also obtained. Two criteria for fluid-elastic instability were applied