Extreme wave action on large horizontal cylinders located above still water level

Abstract

This paper presents the results from an experimental study on plunging wave action o a large horizontal cylinder in the splash zone. Impact pressures are found to range from localized impulsive pressures with time scales in the range of 0.001T to synchronous low frequency pressure oscillation with oscillation time scales around 0.01T (T is the characteristic wave period) The highest peak pressure is obtained when the profile of the incident wave front is concentric to the cylinder boundary. Peak pressures are obtained when a large pocket of air ix entrapped by the plunging wave front at impact. The entrapped air also leads to synchronous pressure oscillations over a substantial region of the cylinder's surface, covering an angular zone of about 105°. Overall, the incident wave profile trajectory and the entrapped air are found to influence the impact load significantly.