Accession Number : ADA132593

Title :   Propagation of Weakly-Nonlinear Surface Water Waves in Regions with Varying Depth and Current.

Descriptive Note : Research rept. 14 Jun 82-13 Jun 83,


Personal Author(s) : Kirby,James Thornton , Jr

PDF Url : ADA132593

Report Date : Jul 1983

Pagination or Media Count : 344

Abstract : This report represents a study of the equations governing the propagation of weakly nonlinear waves in regions where currents exist and where the depth and current are allowed to vary. After deriving a velocity potential applicable to propagating surface waves according to the Stokes expansion, the Lagrangian governing wave motion in the propagation space is derived. A consistent perturbation scheme then leads to the equations governing the wave and current motion at each order in the Stokes series. After neglecting time dependence of the wave amplitude, parabolic equations governing the combined refraction and diffraction of Stokes waves of small amplitude are developed and used to calculate the wavefields for several representative cases illustrating the importance of nonlinear effects. The computational models are verified by comparison to laboratory data of wave amplitude for a wavefield focussed by a submerged shoal, and it is found that the nonlinear model accounts for the major discrepancies found between linear model results and the laboratory data. (Author)

Descriptors :   *Ocean waves, Nonlinear systems, Wave propagation, Ocean currents, Refraction, Diffraction, Reflection, Interactions

Subject Categories : Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE