Current Search: Slinn, D. N. (x)
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Title
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Numerical simulation of wave energy dissipation in turbulent boundary layers.
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Creator
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Moneris, Stephanie Sylvie., Florida Atlantic University, Slinn, D. N., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
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Abstract/Description
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Shoaling surface waves create turbulent shear flows at the sea-bed and thereby contribute to wave energy dissipation in the bottom boundary layer. Turbulent boundary layers are examined using a high-resolution time-dependent three-dimensional numerical model. Simulations estimate the wave energy dissipation in the boundary layer. Results indicate that turbulence levels are coupled to the wave cycle; accelerating flow organizes the boundary layer structure, decelerating flow destabilizes it...
Show moreShoaling surface waves create turbulent shear flows at the sea-bed and thereby contribute to wave energy dissipation in the bottom boundary layer. Turbulent boundary layers are examined using a high-resolution time-dependent three-dimensional numerical model. Simulations estimate the wave energy dissipation in the boundary layer. Results indicate that turbulence levels are coupled to the wave cycle; accelerating flow organizes the boundary layer structure, decelerating flow destabilizes it and flow reversal induces the strongest turbulent bursts. Details of the flow are functions of the Reynolds number, wave frequency, wave complexity, presence of a mean current, and the flow history of the preceding wave period. Mean flow properties are compared between the three-dimensional model and one-dimensional eddy-viscosity based models. Generally, features of the boundary layer are satisfactorily approximated by the eddy-viscosity models, with accuracy depending on the wave amplitude, period, phase, and other forcing conditions.
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Date Issued
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2000
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PURL
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http://purl.flvc.org/fcla/dt/12692
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Subject Headings
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Waves--Mathematical models, Turbulent boundary layer--Mathematical models
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Format
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Document (PDF)
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Title
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Numerical simulations of the wave bottom boundary layer over sand ripples.
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Creator
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Pierro, Thomas P., Florida Atlantic University, Slinn, D. N., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
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Abstract/Description
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Surface gravity waves propagating in the nearshore produce an oscillatory freestream potential flow near the seabed and commonly cause regular two-dimensional sand ripples to be formed. The existence of the ripples causes complex turbulent flows to evolve in the boundary layer, which can dissipate significant energy from the surface waves. A time-dependent DNS model is used to solve the Navier-Stokes equations in three dimensions on a transformed curvilinear grid for specified wave parameters...
Show moreSurface gravity waves propagating in the nearshore produce an oscillatory freestream potential flow near the seabed and commonly cause regular two-dimensional sand ripples to be formed. The existence of the ripples causes complex turbulent flows to evolve in the boundary layer, which can dissipate significant energy from the surface waves. A time-dependent DNS model is used to solve the Navier-Stokes equations in three dimensions on a transformed curvilinear grid for specified wave parameters. When compared to smooth beds, simulations over wavy topographies demonstrate that turbulence is enhanced due to flow separation in the lee of the ripple crests. Shear instabilities during phases of weak flow and vortex shedding in times of strong flow work together to sustain turbulence throughout the wave period. Resulting flows over ripples exhibit an increase in boundary layer thickness and dissipation rates, as energy is lost to viscous effects in maintaining turbulence.
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Date Issued
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2001
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PURL
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http://purl.flvc.org/fcla/dt/12854
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Subject Headings
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Boundary layer--Mathematical models, Waves--Mathematical models, Sand waves
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Format
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Document (PDF)
