Statistical Properties of Wave-Current Force

It is known that when a wave encounters a current, its characteristics change; if the current is in the direction of wave propagation, the wave amplitude decreases and its length increases; but if the current opposes the wave, the wave steepens and shortens. These changes are due to the interactions between current and wave. In this paper, the influence of current and wave-current interactions on the statistical properties of fluid force on an element of a cylinder in a random fluid field is studied analytically. The quantities investigated are the mean, standard deviation, skewness, and probability function of the fluid force with and without wave-current interactions considered. Results are computed numerically and presented graphically. It is shown that the presence of even a moderate current can affect both the probability measures and probability structure of fluid force to an appreciable extent and causes fluid force to deviate further from Gaussian, especially in adverse current and when wave-current interactions are considered.