A lee wave model for deep-sea mudwave activity

Flood, Roger D.

doi:10.1016/0198-0149(88)90071-4

Cited by 168 publications

(117 citation statements)

References 15 publications

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“…It appears that instability and upstream migration in the present framework relies on the presence of internal wave propagation. This connection has also been surmised by Flood (1988), albeit in the context of sediment waves formed by bottom currents with constant stratification. For such a setting, Flood (1988) advanced a qualitative explanation for upstream migration, based on streamline patterns that correspond to upwardpropagating internal waves.…”

Section: Flow Over An Evolving Bedmentioning

confidence: 98%

“…In contrast to turbidity currents, bottom currents are usually not driven by sediment loading, but rather by thermohaline, wind and tidal forces, and they typically attain velocities of 1-20 cm s −1 (Shanmugam 2006). These flows can persist for thousands of years (Flood 1988), contrasting with the episodic nature of turbidity current flows.…”

Section: Introductionmentioning

confidence: 98%

“…Perhaps the most widely referenced model for deep-sea sediment wave formation is due to Flood (1988). This is based on earlier work by Queney (1948), who derived a closed-form, inviscid velocity field for the internal lee waves developing in stratified flow over sinusoidal topography.…”

Section: Introductionmentioning

confidence: 99%

“…Colombini & Stocchino (2008) subsequently extends this work to weakly nonlinear growth of bedforms. The limitation to bedload transport only, and the absence of a density stratification, precludes internal waves from being generated, so that a direct link with the model by Flood (1988) cannot be established.…”

Section: Introductionmentioning

confidence: 99%

“…This tangential velocity reaches a maximum on the downstream side of the sediment wave, where the downward slope has its maximum. Hence, Flood (1988) argued that sedimentation should be weakest at this location, and that it might even be possible for erosion to occur. Conversely, the tangential velocity is smallest on the upstream side of the sediment wave, resulting in maximum sedimentation there.…”

Section: Introductionmentioning

confidence: 99%

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Deep-water sediment wave formation: linear stability analysis of coupled flow/bed interaction

et al. 2011

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A linear stability analysis is carried out for the interaction of an erodible sediment bed with a sediment-laden, stratified flow above the bed, such as a turbidity or bottom current. The fluid motion is described by the full, two-dimensional Navier-Stokes equations in the Boussinesq approximation, while erosion is modelled as a diffusive flux of particles from the bed into the fluid. The stability analysis shows the existence of both Tollmien-Schlichting and internal wave modes in the stratified boundary layer. For the internal wave mode, the stratified boundary layer acts as a wave duct, whose height can be determined analytically from the Brunt-Väisäläf r e q u e n c y criterion. Consistent with this criterion, distinct unstable perturbation wavenumber regimes exist for the internal wave mode, which are associated with different numbers of pressure extrema in the wall-normal direction. For representative turbidity current parameters, the analysis predicts unstable wavelengths that are consistent with field observations. As a key condition for instability to occur, the base flow velocity boundary layer needs to be thinner than the corresponding concentration boundary layer. For most of the unstable wavenumber ranges, the phase relations between the sediment bed deformation and the associated wall shear stress and concentration perturbations are such that the sediment waves migrate in the upstream direction, which again is consistent with field observations.

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Section: Flow Over An Evolving Bedmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Deep-water sediment wave formation: linear stability analysis of coupled flow/bed interaction

et al. 2011

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Slowdown of Circumpolar Deepwater flow during the Late Neogene: Evidence from a mudwave field at the Argentine continental slope

Gruetzner

Uenzelmann-Neben

Franke

et al. 2014

Geophys. Res. Lett.

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Geochemical evidence from boreholes suggests enhanced transport of Northern Component Water (NCW) to southern latitudes from about 6 Ma onward. However, information on how this change in transport influenced the intensity and position of current systems is sparse. Here we use seismic reflection profiles interpreted together with bathymetric data to investigate current derived deposits at the central Argentine Margin. Upslope migrating mudwaves overlying a late Miocene erosional unconformity provide evidence that Circumpolar Deepwater flow slowed down with the onset of NCW inflow. During the last 3 Ma, changes in dimensions and migration rates of the waves are small indicating continuous bottom current flow conditions similar to today with only minor variations in flow speed, suggesting that the Deep Western Boundary Current in the western south Atlantic as observed today has been a pervasive feature of the global thermohaline circulation system during the Plio-/Pleistocene.

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Eddy‐driven sediment transport in the Argentine Basin: Is the height of the Zapiola Rise hydrodynamically controlled?

et al. 2015

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In this study, we address the question whether eddy-driven transports in the Argentine Basin can be held responsible for enhanced sediment accumulation over the Zapiola Rise, hence accounting for the existence and growth of this sediment drift. To address this question, we perform a 6 year simulation with a strongly eddying ocean model. We release two passive tracers, with settling velocities that are consistent with silt and clay size particles. Our experiments show contrasting behavior between the silt fraction and the lighter clay. Due to its larger settling velocity, the silt fraction reaches a quasisteady state within a few years, with abyssal sedimentation rates that match net input. In contrast, clay settles only slowly, and its distribution is heavily stratified, being transported mainly along isopycnals. Yet, both size classes display a significant and persistent concentration minimum over the Zapiola Rise. We show that the Zapiola Anticyclone, a strong eddy-driven vortex that circulates around the Zapiola Rise, is a barrier to sediment transport, and hence prevents significant accumulation of sediments on the Rise. We conclude that sediment transport by the turbulent circulation in the Argentine Basin alone cannot account for the preferred sediment accumulation over the Rise. We speculate that resuspension is a critical process in the formation and maintenance of the Zapiola Rise.

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A lee wave model for deep-sea mudwave activity

Cited by 168 publications

References 15 publications

Deep-water sediment wave formation: linear stability analysis of coupled flow/bed interaction

Deep-water sediment wave formation: linear stability analysis of coupled flow/bed interaction

Slowdown of Circumpolar Deepwater flow during the Late Neogene: Evidence from a mudwave field at the Argentine continental slope

Eddy‐driven sediment transport in the Argentine Basin: Is the height of the Zapiola Rise hydrodynamically controlled?

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