Turbulent flow over a wavy surface: Stratified case

Calhoun, Ronald; Street, Robert L.; Koseff, Jeffrey R.

doi:10.1029/2001jc900002

Cited by 18 publications

(6 citation statements)

References 16 publications

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“…Perhaps this, too, would be an argument for developing a long-wave free-surface LES model as mentioned in the second paragraph of this section. At the present time, oceanic LES examples for flow over such topography are rare, even in the absence of surface wave effects – but see Calhoun & Street (2001), Calhoun, Street & Kosoff (2001) and Skyllingstad & Wijesekera (2004).…”

Section: Summary and Prospectsmentioning

confidence: 99%

Surface waves and currents in aquatic vegetation

McWilliams¹

2023

J. Fluid Mech.

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A multiscale asymptotic theory is formulated for surface gravity waves and currents in finite-depth water with a vegetation canopy that provides a drag force on both flows with known drag coefficients. It assumes that the density is uniform and the depth is uniform pro tem and that the wave frequency is fast compared to the current advective rate. It is a quasi-linear theory in which the wave dynamics is independent of current and drag to leading order but provides perturbative corrections, and in which wave nonlinear interactions are neglected while quadratic wave-averaged wave fluxes and quadratic wave-drag effects are retained. The primary surface wave is modified by drag and current interactions, and the wave-averaged current momentum balance includes a wave-augmented drag force and several vortex forces due to Earth's rotation, current vorticity, Stokes drift and drag-induced wave vorticity. The wave-averaged current equations derived here are a suitable basis for future large-eddy simulation and submesoscale circulation computational models.

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Section: Summary and Prospectsmentioning

confidence: 99%

Surface waves and currents in aquatic vegetation

McWilliams¹

2023

J. Fluid Mech.

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“…The present study is concerned with the role of bed roughness in interfacial mixing and thus the friction Richardson number Ri τ is used to compare the relative strengths of buoyant and frictional forces (Calhoun et al, 2001):…”

Section: Results and Interpretationmentioning

confidence: 99%

The influence of dunes on mixing in a migrating salt‐wedge: Fraser River estuary, Canada

Kostaschuk

Best

Villard³

2010

Earth Surf Processes Landf

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Dune bedforms and salt-wedge intrusions are common features in many estuaries with sand beds, and yet little is known about the interactions between the two. Flow visualization with an echosounder and velocity measurements with an acoustic Doppler current profi ler over areas of fl at-bed and sand dunes in the highly-stratifi ed Fraser River estuary, Canada, were used to examine the effect of dunes on interfacial mixing. As the salt-wedge migrates upstream over the fl at-bed, mixing is restricted to the lower portion of the water column. However, as the salt-wedge migrates into the dune fi eld from the fl at bed, there is a dramatic change in the fl ow, and large internal in-phase waves develop over each of the larger dunes, with water from the saltwedge reaching the surface of the estuary. The friction Richardson number shows that bed friction is more important in interfacial mixing over the dunes than over the fl at-bed, and a plot of internal Froude Number versus obstacle (dune) height shows that the salt-wedge fl ow over the dunes is mainly supercritical. Such bedforms can be expected to cause similar effects in interfacial mixing in other estuaries and sediment-laden density currents, and may thus be infl uential in fl uid mixing and sediment transport.

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“…2008). Following previous wind–wave studies (Henn & Sykes 1999; Calhoun, Street & Koseff 2001; Yang et al. 2013), we use a computational domain , where is the wavelength.…”

Section: Methodology and Problem Set-upmentioning

confidence: 99%

“…c/u * = 41.6 in case CU42) that are typically found under swell-dominated sea conditions (Sullivan et al 2008). Following previous wind-wave studies (Henn & Sykes 1999;Calhoun, Street & Koseff 2001;Yang et al 2013), we use a computational domain (L x , L y , L z ) = (2λ, λ, λ), where λ is the wavelength. The domain size in the streamwise direction enables the simulation of turbulence coherent motions larger than λ, and is sufficiently large to produce the correct temporal correlation in the turbulence statistics (Hao, Cao & Shen 2021).…”

Section: Large-eddy Simulation On a Boundary-fitted Gridmentioning

confidence: 99%

Large-eddy simulation of gusty wind turbulence over a travelling wave

Hao

Shen

2022

J. Fluid Mech.

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Wind gustiness in the marine atmospheric boundary layer affects significantly the dynamics of air–sea interaction. To understand the impacts of wind gust events, we perform large-eddy simulation of wind turbulence over a travelling wave to investigate the response of the wind field to an impulsive wind speed increase or decrease. It is found that the turbulence fluctuations and the terms in the turbulent kinetic energy budget equation have a delayed response to the change in the mean flow, while the response of the wave-coherent motions is quasi-stationary. The wave-coherent motions are investigated quantitatively through comparison with a viscous curvilinear model developed by Cao et al. (J. Fluid Mech., vol. 901, 2020, A27) and Cao & Shen (J. Fluid Mech., vol. 919, 2021, A38). We observe an asymmetric hysteresis between the growing wind and the decaying wind in the evolution of the form drag and the viscous drag. We find further that the variation of the wave growth rate during the wind gust is related closely to the contribution from the out-of-phase component of the vertical velocity. Our discoveries provide evidence for the necessity of improving non-equilibrium turbulence and wind input modelling to account for the wind gustiness effect in future studies.

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Turbulent flow over a wavy surface: Stratified case

Cited by 18 publications

References 16 publications

Surface waves and currents in aquatic vegetation

Surface waves and currents in aquatic vegetation

The influence of dunes on mixing in a migrating salt‐wedge: Fraser River estuary, Canada

Large-eddy simulation of gusty wind turbulence over a travelling wave

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