Generation of Wave Amplitude and Orbital Particle Velocity Field of a Random Sea.

摘要

In designing vehicles capable of weathering rough seas produced by intense, persevering storms, some method of generating a representation of the important effects of a random sea must be employed. The proposed technique models the wave amplitude as a function of horizontal location and time and evaluates the accompanying horizontal and vertical components of orbital particle velocity as a function of horizontal and vertical location and time. The underlying definition of a random sea is in terms of a Gaussian, stationary random process with a Pierson-Moskowitz spectral density function for the wave amplitude at some reference point. The method is suitable for computing probability distributions for the vehicle state variables whether or not the vehicle dynamics are governed by a linear differential equation. If the dynamics are linear, the actual Gaussian stationary probability distribution can be computed through solution of an algebraic system. For the nonlinear case, random number generation and numerical integration produce time averages to approximate ensemble averages in estimating any number of statistical moments. (Author)