Computations of the response of a wave spectrum to a sudden change in wind direction.

Abstract

The response of a wind sea spectrum to a step function change in wind direction is investigated theoretically for a sequence of direction changes ranging from 30 DEGREE to 180 DEGREE in increments of 30 DEGREE . Two spectral energy balance models are used: the model EXACT-NL, in which the nonlinear transfer is represented exactly, and the model 3G-WAM, in which the nonlinear transfer is approximated by the discrete interaction parameterization. In both models, the input and dissipation source functions are taken from the energy balance proposed by Komen. The operational model 3G-WAM reproduces fairly closely the EXACT-NL results. For wind direction changes less than 60 DEGREE , the wind sea ..