FLUID DAMPING AND FLUID STIFFNESS OF A TUBE ROW IN CROSS-FLOW

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.