Random Wave Slamming on Cylinders

Abstract

This paper describes random wave forces acting on a fixed, slender, horizontal circular cylinder in the vicinity of the free surface, taking account of the intermittency of submergence and wave slamming. Expressions are derived for the probability density and the mean of the force maxima, and the calculation of the expected value of the single largest force maximum occurring within a given duration is also described. These various predictions are based on the assumptions of linear wave theory and a narrow‐band wave spectrum. Depending on the elevation of the cylinder and the wave height, the force maxima in individual waves may be associated with either inertia, combined drag‐inertia during complete submergence, the instant of complete submergence, partial submergence, or slamming. The probability density of force maxima incorporates force ranges within which the maxima are associated with one or other of these effects. Numerical results relating to these statistical properties are presented, and the effects of intermittent submergence and wave slamming are discussed.