Mixing in Stratified Jets

Roberts, Philip J. W.; Maile, K.; Daviero, Gregory J.

doi:10.1061/(asce)0733-9429(2001)127:3(194)

Cited by 15 publications

(6 citation statements)

References 15 publications

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“…Instantaneous measurements often greatly exceed average values. This variability is probably due to internal waves, turbulent near-field mixing, and advection of patches of water with different dye concentrations past the sampling instrument (see Roberts et al, 2001, for further discussion of this phenomenon.) Dilutions obtained from physical or mathematical models are reported as time-averaged values, with temporal fluctuations removed.…”

Section: Hydraulic Mixing Zone (Hmz) Surveysmentioning

confidence: 99%

Plume tracking and dilution of effluent from the Boston sewage outfall

Hunt

Mansfield

Mickelson

et al. 2010

Marine Environmental Research

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Section: Hydraulic Mixing Zone (Hmz) Surveysmentioning

confidence: 99%

Plume tracking and dilution of effluent from the Boston sewage outfall

Hunt

Mansfield

Mickelson

et al. 2010

Marine Environmental Research

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“…It is assumed here that for pure jets (non-stratified), the densimetric Froude number approaches infinity. The incoming densimetric Froude number was always well above the limit of Fr 0 ≥ 1.2 that separates gravity-controlled from momentum-controlled flows (List, 1982;Powell, 1990;Roberts et al, 2001). Therefore, all jets can be considered as momentum-dominated flows.…”

Section: Tested Flow Conditionsmentioning

confidence: 94%

“…Seminal theoretical studies have used input mass, momentum and density flux parameters to characterize the proximal jet regions (Baines, 1995(Baines, , 2002, but some studies have proposed empirically-derived values of the densimetric Froude to describe limiting conditions between momentum versus gravity control: Fr 0 ≥ 1.3 for axisymmetrical jets and Fr 0 ≥ 1.2 for wall jets (corresponding to Ri 0 ≤ 0.56 for axisymmetrical jets and Ri 0 ≤ 0.735 for wall jets), respectively (List, 1982;Powell, 1990;Roberts et al, 2001). Further controlling factors proposed for describing these flow transitions include sediment concentration, grain size, and the density difference between the fluid and the sediment (Bates, 1953;Powell, 1990;Chiew & Lim, 1996;Hoyal et al, 2003).…”

Section: Jets and Their Depositsmentioning

confidence: 99%

“…This flow evolution is also referred to as the near‐field and far‐field of a jet. The near‐field is the region where inertia and mixing processes are controlled by the discharge parameters at the orifice (Roberts et al., 2001). It is commonly assumed that density contrasts have a limited effect on flow structure and morphodynamics in the near‐field.…”

Section: Jets and Their Depositsmentioning

confidence: 99%

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Three‐dimensional submerged wall jets and their transition to density flows: Morphodynamics and implications for the depositional record

2021

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Jets that expand from an orifice into an ambient water body represent a basic flow model for depositional environments related to expanding flows. Momentum-dominated jets evolve into gravity-dominated density flows. To understand this transition and its sedimentological relevance, three-dimensional tank experiments with submerged wall jets were conducted, systematically varying parameters such as the initial density difference, bed slope, grain size and sediment supply. Bedform successions could be subdivided into those related to the jet and those related to the density flow. Jet deposits included early-stage bedforms, scours and mouth bars. Early-stage bedforms are asymmetrical dunes that spread concentrically from the orifice. Sediment entrainment by eddies from the expanding jets led to the formation of scours and mouth bars. Flows with lesser initial density difference produced more elongate scours. Conversely, scours became deeper for denser incoming flows. Coarser-grained sediment caused the formation of higher and steeper mouth bars and vice versa. The transition from momentum-dominated jets to gravity-dominated density flows occurred approximately at the mouth-bar crest. Hydraulic jumps were absent in the expanding jet regions and at the transitions to density flows. Instead, complex flow patterns and circulations were inferred from the velocity measurements within the scour and at the mouth-bar crests. Bedform trains related to the density flow were controlled by the grain size and sediment supply. Coarse-grained sediment and high supply rates caused strong mouth-bar aggradation and flow splitting, leading to the formation of bedform trains laterally adjacent to the mouth bar. Finegrained sediment and low supply rates caused the formation of bedform trains downflow of the mouth bar. The symmetrical bedforms deposited by the density flows always displayed an in-phase relationship with the flow, indicating that they were antidunes. The experimental jet deposits resemble successions known from subaqueous ice-contact fans and deep water channel-lobe transition zones.

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“…Regarding the spread of thermal effluents in the steady flow, there have been various theoretical analysis, numerical simulation, and experimental measurements, with focus on velocity distribution in axial and radial directions (EI-Amin et al, 2010), gradient of hydrothermal field (Jiang et al, 2003;Tang et al, 2008), fluxes of mass, momentum, and buoyancy (EI-Amin et al, 2010), bifurcation of jet (Wang et al, 2012), coherent vortex structures (Yuan et al, 1999), trajectory and cling length (Gildeh et al, 2014), entrainment (McGuirk andRodi, 1979), and obstructed buoyant jets (Huai and Fang, 2006;Huai et al, 2006). Similar investigations were also been performed for contaminant discharge (Lee and Cheung, 1986;Jirka and Akar, 1991;Yoda et al, 1994;Méndez-Díaz and Jirka, 1996;Roberts et al, 1997Roberts et al, , 2001Arakeri et al, 2000;Diez et al, 2005;Papanicolaou et al, 2008;Lai and Lee, 2012;Lee, 2012;Abessi and Roberts, 2014).…”

Section: Introductionmentioning

confidence: 99%