Fluidelastic vibrations for an array of tubes (1st report, flow direction and fluid density effects on the fluidelastic vibrations of a triangular array of tubes)

Water tunnel and wind tunnel experiments were conducted on a triangular array of tubes with a 1.3 pitch to diameter ratio, which simulates nuclear components. The array could be rotated about an axis parallel to the tubes and perpendicular to the flow direction, so that the incident flow direction effects on cross-flow tube response could be studied. The same test section, with the array of tubes, could be set up in a water tunnel and wind tunnel, so that the fluid density effects on tube response could be studied. From the above experiments, the flow direction and the fluid density effects on fluidelastic vibrations were clarified. In both water and air, the fluidelastic threshold for the normal triangular array was about 1.5 times that of the parallel triangular array. Moreover, it was confirmed that the reduced velocity depended on damping parameter to the power of 0.5 from both the water and air results.