Added Mass and Hydrodynamic Damping of Perforated Plates Vibrating in Water

Abstract

Experiments are described in which the fluid dynamic forces acting on perforated plates vibrating in water were measured. The test results are expressed in terms of added mass and hydrodynamic damping. Dimensionless formulas are presented which give accurate values for the added mass of the plates tested and which yield satisfactorily conservative lower bounds for the hydrodynamic damping force in both the linear and nonlinear (large-amplitude) damping range. The formulas for added mass and for low-amplitude damping apply to plates of any thickness that have any uniform square pattern of circular perforations. All of the results are general in that fluid density, viscosity, vibration amplitude, and frequency are all free parameters.