scholarly journals On the Interaction of Surface Waves and Upper Ocean Turbulence

2006 ◽  
Vol 36 (3) ◽  
pp. 551-557 ◽  
Author(s):  
Fabrice Ardhuin ◽  
Alastair D. Jenkins
Keyword(s):  
Surface Waves ◽  
Wave Energy ◽  
Stokes Drift ◽  
Mean Flow ◽  
Ocean Turbulence ◽  
Random Surface ◽  
Averaged Equations ◽  
New Interpretation ◽  
Wave Models ◽  
Wave Induced

Abstract The phase-averaged energy evolution for random surface waves interacting with oceanic turbulence is investigated. The change in wave energy balances the change in the production of turbulent kinetic energy (TKE). Outside the surface viscous layer and the bottom boundary layer the turbulent flux is not related to the wave-induced shear so that eddy viscosity parameterizations cannot be applied. Instead, it is assumed that the wave motion and the turbulent fluxes are not correlated on the scale of the wave period. Using a generalized Lagrangian average it is found that the mean wave-induced shears, despite zero vorticity, yield a production of TKE as if the Stokes drift shear were a mean flow shear. This result provides a new interpretation of a previous derivation from phase-averaged equations by McWilliams et al. It is found that the present source or sink of wave energy is smaller but is still on the order of the empirically adjusted functions used for the dissipation of swell energy in operational wave models, as well as observations of that phenomenon by Snodgrass et al.

scholarly journals Streaming by leaky surface acoustic waves

2010 ◽  
Vol 467 (2130) ◽  
pp. 1779-1800 ◽  
Author(s):  
J. Vanneste ◽  
O. Bühler
Keyword(s):  
Surface Waves ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Stokes Drift ◽  
Mean Flow ◽  
Matched Asymptotics ◽  
Flow Generation ◽  
Solid Liquid Interface ◽  
Solid Liquid

Acoustic streaming, the generation of mean flow by dissipating acoustic waves, provides a promising method for flow pumping in microfluidic devices. In recent years, several groups have been experimenting with acoustic streaming induced by leaky surface waves: (Rayleigh) surface waves excited in a piezoelectric solid interact with a small volume of fluid where they generate acoustic waves and, as result of the viscous dissipation of these waves, a mean flow. We discuss the computation of the corresponding Lagrangian mean flow, which controls the trajectories of fluid particles and hence the mixing properties of the flows generated by this method. The problem is formulated using the averaged vorticity equation which extracts the dominant balance between wave dissipation and mean-flow dissipation. Particular attention is paid to the thin boundary layer that forms at the solid/liquid interface, where the flow is best computed using matched asymptotics. This leads to an explicit expression for a slip velocity, which includes the effect of the oscillations of the boundary. The Lagrangian mean flow is naturally separated into three contributions: an interior-driven Eulerian mean flow, a boundary-driven Eulerian mean flow and the Stokes drift. A scale analysis indicates that the latter two contributions can be neglected in devices much larger than the acoustic wavelength but need to be taken into account in smaller devices. A simple two-dimensional model of mean flow generation by surface acoustic waves is discussed as an illustration.

scholarly journals The Contribution of High-Frequency Wind-Generated Surface Waves to the Stokes Drift

2020 ◽  
Vol 50 (12) ◽  
pp. 3455-3465
Author(s):  
Luc Lenain ◽  
Nick Pizzo
Keyword(s):  
Surface Waves ◽  
Wave Spectrum ◽  
Ocean Dynamics ◽  
Stokes Drift ◽  
Upper Ocean ◽  
Sea State ◽  
Instrument Measurement ◽  
Wave Models ◽  
Surface Wave Field

AbstractThe effects of nonbreaking surface waves on upper-ocean dynamics enter the wave-averaged primitive equations through the Stokes drift. Through the resulting upper-ocean dynamics, Stokes drift is a catalyst for the fluxes of heat and trace gases between the atmosphere and ocean. However, estimates of the Stokes drift rely crucially on properly resolving the wave spectrum. In this paper, using state-of-the-art spatial measurements (in situ and airborne remote sensing) from a number of different field campaigns, with environmental conditions ranging from 2 to 13 m s−1 wind speed and significant wave height of up to 4 m, we characterize the properties of the surface wave field across the equilibrium and saturation ranges and provide a simple parameterization of the transition between the two regimes that can easily be implemented in numerical wave models. We quantify the error associated with instrument measurement limitations, or incomplete numerical parameterizations, and propose forms for the continuation of these spectra to properly estimate the Stokes drift. Depending on the instrument and the sea state, predictions of surface Stokes drift may be underestimated by more than 50%.

scholarly journals Wave-induced mixing and transport of buoyant particles: application to the Statfjord A oil spill

Ocean Science ◽  
2014 ◽  
Vol 10 (6) ◽  
pp. 977-991 ◽  
Author(s):  
M. Drivdal ◽  
G. Broström ◽  
K. H. Christensen
Keyword(s):  
Oil Spill ◽  
Wave Spectrum ◽  
Wave Model ◽  
Stokes Drift ◽  
Ocean Turbulence ◽  
Wave Effects ◽  
Ekman Theory ◽  
Energy And Momentum ◽  
Drift Models ◽  
Wave Induced

Abstract. This study focuses on how wave–current and wave–turbulence interactions modify the transport of buoyant particles in the ocean. Here the particles can represent oil droplets, plastic particles, or plankton such as fish eggs and larvae. Using the General Ocean Turbulence Model (GOTM), modified to take surface wave effects into account, we investigate how the increased mixing by wave breaking and Stokes shear production, as well as the stronger veering by the Coriolis–Stokes force, affects the drift of the particles. The energy and momentum fluxes, as well as the Stokes drift, depend on the directional wave spectrum obtained from a wave model. As a first test, the depth and velocity scales from the model are compared with analytical solutions based on a constant eddy viscosity (i.e., classical Ekman theory). Secondly, the model is applied to a case in which we investigate the oil drift after an oil spill off the west coast of Norway in 2007. During this accident the average net drift of oil was observed to be both slower and more deflected away from the wind direction than predicted by oil-drift models. In this case, using wind and wave forcing from the ERA Interim archive it is shown that the wave effects are important for the resultant drift and have the potential to improve drift forecasting.

scholarly journals Wave induced mixing and transport of buoyant particles: application to the Statfjord A oil spill

2014 ◽  
Vol 11 (3) ◽  
pp. 1265-1300
Author(s):  
M. Drivdal ◽  
G. Broström ◽  
K. H. Christensen
Keyword(s):  
Oil Spill ◽  
Wave Spectrum ◽  
Wave Model ◽  
Stokes Drift ◽  
Western Coast ◽  
Ocean Turbulence ◽  
Wave Effects ◽  
Ekman Theory ◽  
Energy And Momentum ◽  
Wave Induced

Abstract. The modelling of wave-current and wave-turbulence interactions have received much attention in recent years. In this study the focus is on how these wave effects modify the transport of particles in the ocean. Here the particles are buoyant tracers that can represent oil droplets, plastic particles or plankton, for example fish eggs and larvae. Using the General Ocean Turbulence Model (GOTM), modified to take surface wave effects into account, we investigate how the increased mixing by wave breaking and Stokes shear production as well as the stronger veering by the Coriolis–Stokes force affect the drift of the particles. The energy and momentum fluxes as well as the Stokes drift depend on the directional wave spectrum that can be obtained from a wave model or from observations. As a first test the depth and velocity scales from the model are compared with analytical solutions based on a constant eddy viscosity (e.g. classical Ekman theory). Secondly the model is applied to a case where we investigate the oil drift after an offshore oil spill outside the western coast of Norway in 2007. During this accident the average net drift of oil was observed to be both slower and more deflected away from the wind direction than predicted by empirical models. With wind and wave forcing from the ERA Interim archive, it is shown that the wave effects are important for the resultant drift in this case, and has the potential to improve drift forecasting.

The wave-current interaction in the coastal area

2019 ◽  
Vol 77 (5) ◽  
pp. 375-405
Author(s):  
Homayoon Komijani ◽  
Jaak Monbaliu
Keyword(s):  
Wind Waves ◽  
Stress Gradient ◽  
Circulation Model ◽  
Wave Model ◽  
Stokes Drift ◽  
Test Case ◽  
Mean Flow ◽  
Radiation Stress ◽  
Spectral Wave Model ◽  
Wave Induced

In our investigation of the effect of wind-waves on barotropic mean flow in coastal areas, we compare two methods for calculating wave-induced force. The wave field is simulated by the nearshore spectral wave model SWAN. The wave-induced force (calculated using the radiation stress gradient and dissipation methods) and the Stokes drift are integrated in the COHERENS circulation model in the depth-averaged mode. The coupled set is validated using well-known academic test cases of planar beach and single-barred beach. Finally, in a two-dimensional test case based on Belgian coastal waters we compare simulations of mean flow using the two methods of calculating waveinduced force against field data.<br/> We show clearly that the two methods for calculation of wave-induced force yield very different results even in depth-averaged mode, depending on the angle of incident wave. Simulation of waveinduced circulation using the wave dissipation approach gives better results than using the radiation stress gradient approach. This is clearly visible for strong wave conditions in which the wind is blowing almost parallel to the shore. Under these conditions, the white-capping type of wave breaking is the dominant dissipation mechanism; in the radiation stress gradient, the dissipation signal is not visible, because the energy loss in the spectrum is compensated by wind input.

scholarly journals Eulerian Volume Transport Induced by Spatially Damped Internal Equatorial Kelvin Waves

2015 ◽  
Vol 45 (7) ◽  
pp. 1794-1803 ◽  
Author(s):  
Jan Erik H. Weber
Keyword(s):  
Flow System ◽  
Volume Transport ◽  
Kelvin Waves ◽  
Stokes Drift ◽  
Mean Flow ◽  
Small Perturbations ◽  
The North ◽  
Stokes Transport ◽  
Horizontal Momentum ◽  
Wave Induced

AbstractThe Eulerian volume transport in internal equatorial Kelvin waves subject to viscous attenuation is investigated theoretically by integrating the horizontal momentum equations in the vertical. In terms of small perturbations, the time-averaged horizontal transports are determined to second order in wave steepness. The total Lagrangian volume transport in this problem consists of a Stokes transport plus an Eulerian transport. It is known that the Stokes transport, that is, the vertically integrated Stokes drift, in inviscid internal equatorial Kelvin waves vanishes identically in the rigid-lid approximation for arbitrary vertical variation of the Brunt–Väisälä frequency. The present study considers spatial wave damping due to viscosity. The Stokes transport still becomes zero, but now the radiation stresses due to decaying waves become source terms for the Eulerian mean transport. Calculations of the wave-induced Eulerian transport yield a jetlike symmetric mean flow along the equator from west to east for each baroclinic component, with compensating westward flows on both sides. The flow system scales as the internal equatorial Rossby radius in the north–south direction. The total eastward part of the Eulerian volume flux centered about the equator is estimated to about 0.2 Sv (1 Sv ≡ 106 m3 s−1) for the first baroclinic mode.

scholarly journals Integrating CVMix into GOTM (v6.0): a consistent framework for testing, comparing, and applying ocean mixing schemes

2021 ◽  
Vol 14 (7) ◽  
pp. 4261-4282
Author(s):  
Qing Li ◽  
Jorn Bruggeman ◽  
Hans Burchard ◽  
Knut Klingbeil ◽  
Lars Umlauf ◽  
...  
Keyword(s):  
Surface Waves ◽  
Vertical Mixing ◽  
Ocean Surface ◽  
Ocean Modeling ◽  
Stokes Drift ◽  
Langmuir Turbulence ◽  
Ocean Turbulence ◽  
Ocean Surface Waves ◽  
Ocean Station Papa ◽  
Northern North Sea

Abstract. The General Ocean Turbulence Model (GOTM) is a one-dimensional water column model, including a set of state-of-the-art turbulence closure models, and has widely been used in various applications in the ocean modeling community. Here, we extend GOTM to include a set of newly developed ocean surface vertical mixing parameterizations of Langmuir turbulence via coupling with the Community Vertical Mixing Project (CVMix). A Stokes drift module is also implemented in GOTM to provide the necessary ocean surface waves information to the Langmuir turbulence parameterizations, as well as to facilitate future development and evaluation of new Langmuir turbulence parameterizations. In addition, a streamlined workflow with Python and Jupyter notebooks is also described, enabled by the newly developed and more flexible configuration capability of GOTM. The newly implemented Langmuir turbulence parameterizations are evaluated against theoretical scalings and available observations in four test cases, including an idealized wind-driven entrainment case and three realistic cases at Ocean Station Papa, the northern North Sea, and the central Baltic Sea, and compared with the existing general length scale scheme in GOTM. The results are consistent with previous studies. This development extends the capability of GOTM towards including the effects of ocean surface waves and provides useful toolsets for the ocean modeling community to further study the effects of Langmuir turbulence in a broader scope.

scholarly journals Integrating CVMix into GOTM (v6.0): A consistent framework for testing, comparing, and applying ocean mixing schemes

2021 ◽  
Author(s):  
Qing Li ◽  
Jorn Bruggeman ◽  
Hans Burchard ◽  
Knut Klingbeil ◽  
Lars Umlauf ◽  
...  
Keyword(s):  
Surface Waves ◽  
Vertical Mixing ◽  
Ocean Surface ◽  
Ocean Modeling ◽  
Stokes Drift ◽  
Langmuir Turbulence ◽  
Ocean Turbulence ◽  
Ocean Surface Waves ◽  
Ocean Station Papa ◽  
Northern North Sea

Abstract. The General Ocean Turbulence Model (GOTM) is a one-dimensional water column model including a set of state-of-the-art turbulence closure models, and has widely been used in various applications in the ocean modeling community. Here we extend GOTM to include a set of newly developed ocean surface vertical mixing parameterizations of Langmuir turbulence via coupling with the Community Vertical Mixing Project (CVMix). A Stokes drift module is also implemented in GOTM to provide the necessary ocean surface waves information to the Langmuir turbulence parameterizations, as well as to facilitate future development and evaluation of new Langmuir turbulence parameterizations. In addition, a streamlined workflow with Python and Jupyter Notebook is also described, enabled by the newly developed and more flexible configuration capability of GOTM. The newly implemented Langmuir turbulence parameterizations are evaluated against theoretical scalings and available observations in four test cases, including an idealized wind-driven entrainment case and three realistic cases at ocean station Papa, the northern North Sea and the central Gotland Sea, and compared with the existing General Length Scale scheme in GOTM. The results are consistent with previous studies. This development extends the capability of GOTM towards including the effects of ocean surface waves and provides useful toolsets for the ocean modeling community to further study the effects of Langmuir turbulence in a broader scope.

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