Visualization experimental study on axial flow-induced vibration of slender cantilever rod for reactor

Abstract Experimental visualization is conducted on axial flow-induced vibration (FIV) of a slender cantilever rod in a narrow annular flow channel with a nonintrusive measurement. A real cobalt rodused in PWR was studied. A high-speed camera was employed to capture the vibration displacement response and deformation in a narrow channel. The test rod shows random low-frequency vibration before touching the tube wall, and the vibration amplitude of the test rod continuously increasing with Reynolds number. When the rod touches the tube wall, the vibration amplitude decreases sharply. When Reynolds number is around 1820, the rod shows first-order vibration divergence, which has a large deformation with a tiny vibration amplitude. This work provides a novel and direct approach for measuring the displacement response and deformation of axial FIV in the narrow channel. Moreover, current experiment data can be also used to verify the numerical simulation for axial FIV of elastic slender cantilever rod in water flow.