Force Spectrum of Horizontal Member

Abstract

Expressions of mean value, mean‐square value and spectrum are derived for the vertical force on a horizontal member of square cross section partially immersed in water under the action of a normally incident long‐crested Gaussian stationary linear wave train. The derivation takes into account the possibilities that the member may at times be totally submerged or out of the water. Numerical results are obtained and presented graphically to show that, depending on whether the probabilities associated with the events of total submergence and emergence of the members are considered or ignored, the mean value, mean‐square value and spectrum of the vertical wave force may be significantly different.