Motion-dependent fluid forces acting on a tube array were measured as
a function of excitation frequency, excitation amplitude, and flow vel
ocity. Fluid-damping and fluid-stiffness coefficients were obtained fr
om measured motion-dependent fluid forces as a function of reduced flo
w velocity and excitation amplitude. The water channel and test setup
provide a sound facility for obtaining key coefficients for fluidelast
ic instability of tube arrays in crossflow. Once the motion-dependent
fluid-force coefficients have been measured, a reliable design guideli
ne, based on the unsteady flow theory, can be developed for fluidelast
ic instability of tube arrays in crossflow.