Experimental Study on Flow Induced Vibration of Different Size Strips of Fuel Rod Bundles

To thoroughly study the vibration characteristics of the grid strip of fuel rod bundles, experimental study on flow induced vibration of different size flat strips was conducted, and the vibration characteristics of the strips were acquired. Within the range of experimental tests, the vibration response of the strips could be divided into two parts: turbulence induced vibration and vortex induced vibration. The predominant vibration response induced by turbulence was the first mode of the strips, and the response was amplified with the increasing of the flow velocity. For vortex induced vibration, the St number was from 0.2 to 0.25 in this study, and the lock-in phenomenon was observed. For a strip, the lock-in range of the lower modes was larger than the higher modes. For different thickness strips, the lock-in range of the same modes narrowed down with the increasing of the thickness. For different length strips, the lock-in range of the long strips was larger than that of the short strips of the same modes.