Wind-wave forces on a smooth and rough horizontal submerged cylinder: A field experiment

Small-scale tests conducted directly in the field, rather than in controlled environments such as flumes and wave tanks, provide a more accurate representation of natural conditions that help to understand performance and challenges in the real world. The present work addresses a field experiment conducted to investigate the influence of barnacles on wind-wave forces on a submerged horizontal cylinder. The experiment was carried out in a reserved marine area at the Marine Energy Laboratory (MEL) of the University of Reggio Calabria. The experimental setup consists of iron frames anchored to the seabed and supporting two identical and aligned cylinders. One is smooth and treated against fouling, while the other is given an artificial roughness by printing barnacles on it. The hydrodynamic force coefficients of the Morison equation and the transverse equation were derived from the experimental kinematics and the forces measured by pressure sensors along the cylinder circumference. The main results show that the total wave forces on the rough cylinder increase compared to the smooth cylinder, and the hydrodynamic force coefficients are generally higher. These findings can serve as a benchmark for detailed numerical studies which, once validated by the results of the present field tests, can investigate other configurations more economically and efficiently.