A comparative experimental study of the hydrodynamic force on a solid heave plate, and on heave plates with regularly distributed and fractally distributed perforations

Abstract

The hydrodynamic coefficients (added mass and damping) of oscillating solid and perforated heave plates were investigated using model-scale experiments. Discs with regularly distributed circular holes of various diameters, but with the same overall perforation ratio, were used. Additionally, a fractal geometry incorporating holes of all these diameters was examined. The experiments were conducted in a towing tank using heave force oscillation tests and decay tests using a single degree of freedom mechanism. Potential flow computations performed with WAMIT are also presented. The experimental results are compared to numerical data available in the literature, which suggested that the fractal plate lead to slightly larger damping –a trend not observed in the present study–.