Buoyancy‐driven plumes in rotating, stratified cross flows: Plume dependence on rotation, turbulent mixing, and cross‐flow strength

Lavelle, J. W.

doi:10.1029/96jc03601

Cited by 53 publications

(47 citation statements)

References 66 publications

(37 reference statements)

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“…The theoretical descriptions of plume dynamics they use [Turner, 1973;Helfrich and Battisti, 1991;Lavelle, 1999] assume that the ascending fluid can rise to a neutral buoyancy level. In contrast, T&D assumed that the plume encounters the ice/water interface (producing the chaos regions) before it becomes neutrally buoyant.…”

Section: Stratificationmentioning

confidence: 99%

Hydrothermal plume dynamics on Europa: Implications for chaos formation

et al. 2004

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[1] Hydrothermal plumes may be responsible for transmitting radiogenic or tidally generated heat from Europa's rocky interior through a liquid ocean to the base of its ice shell. This process has been implicated in the formation of chaos regions and lenticulae by melting or exciting convection in the ice layer. In contrast to earlier work, we argue that Europa's ocean should be treated as an unstratified fluid. We have adapted and expanded upon existing work describing buoyant plumes in a rotating, unstratified environment. We discuss the scaling laws governing the flow and geometry of plumes on Europa and perform a laboratory experiment to obtain scaling constants and to visualize plume behavior in a Europa-like parameter regime. We predict that hydrothermal plumes on Europa are of a lateral scale (at least 25-50 km) comparable to large chaos regions; they are too broad to be responsible for the formation of individual lenticulae. Plume heat fluxes (0.1-10 W/m 2 ) are too weak to allow complete melt-through of the ice layer. Current speeds in the plume (3-8 mm/s) are much slower than indicated by previous studies. The observed movement of ice blocks in the Conamara Chaos region is unlikely to be driven by such weak flow.

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Section: Stratificationmentioning

confidence: 99%

Hydrothermal plume dynamics on Europa: Implications for chaos formation

et al. 2004

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“…Even the most advanced current models cannot resolve plumes from individual sources within a vent field and must rely on the assumption of a single point or line source (i.e., the length scale associated with the extent of the source is assumed to be much smaller than the plume rise height) [Lavelle, 1997] Combining hydrographic, flow field, and particle plume observations has yielded a number of novel insights into the dynamical processes acting within the rift valley of the MidAtlantic Ridge, where they control the dispersal of a hydrothermal plume. The analysis of the regional circulation will aid in the interpretation of biological and geochemical data because it constrains the pathways and ages of the measurements.…”

Section: Heat Flux Estimatesmentioning

confidence: 99%

Hydrography and high‐temperature heat flux of the Rainbow hydrothermal site (36°14′N, Mid‐Atlantic Ridge)

Thurnherr¹,

Richards²

2001

J. Geophys. Res.

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Abstract. On the basis of an extensive set of conductivity-temperature-depth, lowered acoustic Doppler current profiler (LADCP), and nephelometry profiles and tow-yos the hydrography, flow field, and particle plume of the Rainbow hydrothermal site on the Mid-Atlantic Ridge are analyzed. In the rift valley the water column is less dense and stratified than both eastern and western off-ridge water, with T/S characteristics consistent with inflow across a sill from the east. The buoyant hydrothermal plumes rise into a strong boundary current flowing along the slope of a topographic high which partially blocks the rift valley below 1950 m. The bulk of the neutrally buoyant plume is advected across a sill which forms both the narrowest and the shallowest part of the valley and acts as a hydraulic control point for the flow below 2000 m. Large-amplitude internal waves consistent with tidal forcing are observed near the sill, but LADCP measurements suggest that the tidal signal is not strong enough to lead to flow reversal at plume depth. Above 2000 rn the mean current across the topography generates lee waves which radiate energy upward and downstream. Density-averaged light-scattering profiles show the hydrothermal particle plume to be Gaussian in depth, even in the near field, where many of the individual profiles are characterized by multiple peaks and the horizontal variability is highest. The temperature anomalies associated with the mean near-source particle plume are of order -$ x 10 -3 øC; that is, the plume is cold/fresh as expected from the background hydrography of the deep Atlantic. Using the flow field, light-scattering, and hydrographic anomaly observations, the heat flux associated with the hydrothermal particle plume at Rainbow is estimated to lie between 1 and $ GW.

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“…Previous studies of buoyancy plumes in the near-field were usually conducted through physical models (e.g., Sobey, et al, 1988;Johnston, et al, 1994), integral numerical models (e.g., Bemporad, 1994;Johnston, et al, 1994) or three-dimensional numerical models (e.g., Stolzenbach and Harleman, 1973;McGuirk and Rodi, 1979;Lavelle, 1997). These results have led to improved understanding of the buoyancy processes, and meanwhile, increased the capabilities of numerically modeling the receiving water circulation and thermal processes in the complete field.…”

Section: Problem Backgroundmentioning

confidence: 99%

3D numerical modeling of circulations associated with a submerged buoyant jet in a shallow coastal environment

Jiang

Fissel

Topham³

2003

Estuarine, Coastal and Shelf Science

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A three-dimensional numerical model was applied to examine the buoyant jetdriven circulation in Port Moody Arm, Canada. The Arm, which has a relatively shallow water environment of 5 30 m depth, receives considerable cooling water from Burrard Thermal Generating Station. The cooling water behaves as a typical submerged buoyant jet and has significant impact on the natural circulation of the receiving water. In order to resolve the sharp gradients in hydrothermal field and overcome the scale barrier between the far-field and near-field zones of the submerged buoyant jet, a newly developed embedded grid scheme was incorporated into the model, which solves the complete field with a single modeling procedure using a pre-conditioned conjugate gradient approach.Special care was taken with the turbulence diffusion and jet entrainment by using a second order turbulence closure model and the Smagorinsky formula. The simulated buoyant jet was calibrated using an integral model matched to empirical jet data; modeled velocity and temperature profiles were quantitatively verified as being in good agreement with the available observations. After the modeled flow pattern was qualitatively verified with data from historical dye-tracing surveys, extensive simulations were carried out to examine circulation behavior under the impact of the buoyant jet.

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Buoyancy‐driven plumes in rotating, stratified cross flows: Plume dependence on rotation, turbulent mixing, and cross‐flow strength

Cited by 53 publications

References 66 publications

Hydrothermal plume dynamics on Europa: Implications for chaos formation

Hydrothermal plume dynamics on Europa: Implications for chaos formation

Hydrography and high‐temperature heat flux of the Rainbow hydrothermal site (36°14′N, Mid‐Atlantic Ridge)

3D numerical modeling of circulations associated with a submerged buoyant jet in a shallow coastal environment

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