Abstract
Many studies have been made with regard to added mass and added damping of the fluid in the case of simple circular cylinders by Chen, Fritz, Mulcahy, etc.; but those effects for the noncircular cylinders are hardly available. In this study, added mass and added damping of the fluid for the coaxial circular cylinders with projection are investigated by both the experiment utilizing one-degree of freedom cylindrical models and the analysis by comparing those for the simple circular cylinders. Also, the method to evaluate the damping ratio of the beam which has the fluid restraint was derived.