Gravity currents interacting with slopes and overhangs

Maggi, Maria Rita; Adduce, Claudia; Lane-Serff, Gregory F.

doi:10.1016/j.advwatres.2022.104339

Cited by 10 publications

(4 citation statements)

References 36 publications

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“…Planar release gravity currents in stratified (Maxworthy et al 2002;Ungarish & Huppert 2002;Birman et al 2007b;Longo et al 2016;Chiapponi et al 2018;Lam et al 2018b;la Forgia et al 2020;Ottolenghi et al 2020;Dai et al 2021;Zahtila et al 2024), and unstratified ambients (Rottman & Simpson 1983;Shin, Dalziel & Linden 2004;La Rocca et al 2008;Dai 2015;Pelmard, Norris & Friedrich 2018;Dai & Huang 2020;De Falco, Adduce & Maggi 2021;Maggi, Adduce & Negretti 2022, 2023aMaggi et al 2023b), as well as cylindrical release gravity currents in unstratified environment have been widely studied experimentally and numerically (Cantero et al 2007a,b;Zgheib, Bonometti & Balachandar 2014, 2015aDai & Huang 2016). However, experimental and numerical studies on stratified gravity currents with the cylindrical release are limited, and therefore we are interested in cylindrical gravity currents propagating into a linearly stratified ambient.…”

Section: Introductionmentioning

confidence: 94%

“…2024), and unstratified ambients (Rottman & Simpson 1983; Shin, Dalziel & Linden 2004; La Rocca et al. 2008; Dai 2015; Pelmard, Norris & Friedrich 2018; Dai & Huang 2020; De Falco, Adduce & Maggi 2021; Maggi, Adduce & Negretti 2022, 2023 a ; Maggi et al. 2023 b ), as well as cylindrical release gravity currents in unstratified environment have been widely studied experimentally and numerically (Cantero et al.…”

Section: Introductionmentioning

confidence: 99%

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Effect of stratification on the propagation of a cylindrical gravity current

Lam,

Chan,

Sutherland

et al. 2024

J. Fluid Mech.

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Direct numerical simulations (DNSs) of three-dimensional cylindrical release gravity currents in a linearly stratified ambient are presented. The simulations cover a range of stratification strengths $0< S\leq 0.8$ (where $S=(\rho _b^*-\rho _0^*)/(\rho _c^*-\rho _0^*), \rho _b^*, \rho _0^*$ and $\rho _c^*$ are the dimensional density at the bottom of the domain, top of the domain and the dense fluid, respectively) at two different Reynolds numbers. A comparison between the stratified and unstratified cases illustrates the influence of stratification strength on the dynamics of cylindrical gravity currents. Specifically, the front velocity in the slumping phase decreases with increasing stratification strength whereas the duration of the slumping phase increases with increments of $S$ . The Froude number calculated in this phase shows a good agreement with models proposed by Ungarish & Huppert (J. Fluid Mech., vol. 458, 2002, pp. 283–301) and Ungarish (J. Fluid Mech., vol. 548, 2006, pp. 49–68), originally developed for planar gravity currents in a stratified ambient. In the inertial phase, the front velocity across cases with different stratification strengths adheres to a power-law scaling with an exponent of $-$ 1/2. Higher Reynolds numbers led to more frequent lobe splitting and merging, with lobe size diminishing as stratification strength increased. Strong interactions among inner vortex rings occurred during the slumping phase, leading to the early formation of hairpin vortices in weakly stratified cases, while strongly stratified cases exhibited delayed vortex formation and less turbulence.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Effect of stratification on the propagation of a cylindrical gravity current

Lam,

Chan,

Sutherland

et al. 2024

J. Fluid Mech.

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“…These frequent and diverse occurrences of gravity currents in the natural environment have motivated numerous investigations, of interdisciplinary nature, of these gravity flows. Several studies have shown how the propagation of dense, bottom gravity currents is affected by topographic aspects [15][16][17][18][19][20][21][22] , by sloping boundaries [23][24][25][26][27][28][29][30][31] as well as rapidly changing slopes [32][33][34][35] . Most of these studies have focused on the mean flow dynamics and the related entrainment of ambient fluid that strongly affects the flow development and fluid properties.…”

Section: Introductionmentioning

confidence: 99%

Turbulence characteristics and mixing properties of gravity currents over complex topography

et al. 2023

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Understanding gravity currents developing on complex topography, that involve turbulence and mixing processes on a wide range of spatial and temporal scales, is of importance for estimating near ground fluxes in oceanic and atmospheric circulation. We present experimental results, based on high resolution velocity and density measurements, of constant upstream buoyancy supply gravity currents flowing from a horizontal boundary onto a tangent hyperbolic shaped slope. The mean flow, the turbulence characteristics and mixing properties, the latter expressed in terms of mixing lengths and eddy coefficients, are determined, highlighting their dependency on topography. These mean flow and mixing characteristics are compared with the field measurements in katabatic winds of Charrondière et al. (2022), showing that the mean katabatic flow structure is substantially different from that of the upstream buoyancy supply gravity current. However interestingly, dimensionless mixing lengths and eddy coefficients compare well despite the difference in mean flow structure and a two order of magnitude difference in the Reynolds number.

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“…In estuary areas, salt-water intrusion into freshwater degrades water quality. Gravity currents are common in lakes, estuaries [5], and oceans with a specific bed slope [6,7]. Furthermore, gravity currents have a density interface where temperature and salinity change in discontinuities of densities, preventing material transportation in a perpendicular direction, which has an impact on the supply of nutrition [8] and oxygen [9,10].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Effects of the Head Edge Behavior of Gravity Current

Koue¹

2023

GEOMATE

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The flow of the gravity current plays an important role in the transportation and mixing of dissolved or suspended nutrients and chemical substances. In this study, from the experiments and numerical simulations of locked-exchange flow, the flow structure at the head of the gravity current was investigated. In a rectangular channel, a finite volume of fluid was instantaneously released into another fluid of slightly different density. A comparison of theoretical methods, experiments and numerical simulations showed that the water depth and volume of the released fluid affected the velocity of the gravity current. In the initial stage, the head moved forward at a constant velocity and then decelerated. In the final stage, which was governed by viscosity, the front velocity decreased proportionally to the time to the power of 1/2 when the head was not disturbed from behind. Gravity current created a mass concentration at the head in the initial stage. As the mass concentration at the head decreased, the gravity current was slowed down by the viscous stage due to the effect of the bottom friction according to the theoretical analysis. In the viscous stage, the mass concentration at the head no longer existed. The transition stage from the initial stage to the viscous stage was shown to vary with the Reynolds number by the numerical simulation. Clarification of the behavior of the leading edge of gravity flow will help predict the formation of mass transport in oceans and lakes, contributing to the conservation of the aquatic environment.

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Gravity currents interacting with slopes and overhangs

Cited by 10 publications

References 36 publications

Effect of stratification on the propagation of a cylindrical gravity current

Effect of stratification on the propagation of a cylindrical gravity current

Turbulence characteristics and mixing properties of gravity currents over complex topography

Dynamic Effects of the Head Edge Behavior of Gravity Current

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