Accession Number : ADA523469


Title :   A Study of Two-Dimensional Unsteady Breaking Waves in Finite-Depth Water


Descriptive Note : Doctoral thesis


Corporate Author : MICHIGAN UNIV ANN ARBOR


Personal Author(s) : Tian, Zhigang


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a523469.pdf


Report Date : Jan 2010


Pagination or Media Count : 233


Abstract : Laboratory experiments are conducted to study two-dimensional unsteady breaking waves in finite-depth water. An eddy viscosity model to simulate energy dissipation in breaking waves is proposed. Numerical simulations are performed to compare to the experimental results and good agreement is found. An energy-convergence rate based wave breaking criterion is evaluated. Our study revealed that the breaking criterion is sensitive to the choice of local wavenumber, but a particular local wavenumber based on local wave geometry distinguishes breaking waves groups from non-breaking ones. This study is published in Physics of Fluids (Tian Z., Perlin, M. & Choi, W. 2008, 20, 066604). Kinematics and dynamics of breaking wave groups are studied. Characteristic time and length scales associated with the wave groups and the breaking waves are defined and determined. Correlations among the characteristic scales are demonstrated. Energy dissipation in breaking waves is quantified and is shown to scale accurately with the characteristic scales. Time and length scales of the breaking crests are used to determine and parameterize the energy dissipation rate. The resulting normalized dissipation rate is on the order of 10-3. This study has been accepted to the Journal of Fluid Mechanics for publication.


Descriptors :   *DEEP WATER , *VISCOSITY , *EDDIES(FLUID MECHANICS) , *WATER WAVES , FLUID MECHANICS , NUMERICAL ANALYSIS , TWO DIMENSIONAL , KINEMATICS , DISSIPATION


Subject Categories : Physical and Dynamic Oceanography


Distribution Statement : APPROVED FOR PUBLIC RELEASE