Marine Wastewater Discharges from Multiport Diffusers. IV: Stratified Flowing Water

Tian, Xiaodong; Roberts, Philip J. W.; Daviero, Gregory J.

doi:10.1061/(asce)0733-9429(2006)132:4(411)

Cited by 22 publications

(14 citation statements)

References 18 publications

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“…CorJet predicts the following properties at the terminal layer, using the same transition rules as for the round jet: centerline terminal dilution S t = 1.5( b / * q )F 1/2 a , maximum level of upper plume boundary z max = 2.7 b /F 1/2 a , and terminal level z t = 2.0 b /F 1/2 a . These values can be compared against the data of Tian et al [57] who determined the corresponding coefficients to be 1.23, 2.4 and 1.4, respectively, indicating satisfactory overall agreement for this complex discharge configuration.…”

Section: Multiport Diffuser Flows In Ambient Current Merging Of Multimentioning

confidence: 79%

Integral Model for Turbulent Buoyant Jets in Unbounded Stratified Flows Part 2: Plane Jet Dynamics Resulting from Multiport Diffuser Jets

2006

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An integral model for the plane buoyant jet dynamics resulting from the interaction of multiple buoyant jet effluxes spaced along a diffuser line is considered as an extension of the round jet formulation that was proposed in Part I. The receiving fluid is given by an unbounded ambient environment with uniform density or stable density stratification and under stagnant or steady sheared current conditions. Applications for this situation are primarily for submerged multiport diffusers for discharges of liquid effluents into ambient water bodies, but also for multiple cooling tower plumes and building air-conditioning. The CorJet model formulation describes the conservation of mass, momentum, buoyancy and scalar quantities in the turbulent jet flow in the plane jet geometry. It employs an entrainment closure approach that distinguishes between the separate contributions of transverse shear and of internal instability mechanisms, and contains a quadratic law turbulent pressure force mechanism. But the model formulation also includes several significant three-dimensional effects that distinguish actual diffuser installations in the water environment. These relate to local merging processes from the individual multiple jets, to overall finite length effects affecting the plume geometry, and to bottom proximity effects given by a "leakage factor" that measures the combined affect of port height and spacing in allowing the ambient flow to pass through the diffuser line in order to provide sufficient entrainment flow for the mixing downstream from the diffuser. The model is validated in several stages: First, comparison with experimental data for the asymptotic, self-similar stages of plane buoyant jet flows, i.e. the plane pure jet, the pure plume, the pure wake, the advected line puff, and the advected line thermal, support the choice of the turbulent closure coefficients contained in the entrainment formulation. Second, comparison with data for many types of non-equilibrium flows with a plane geometry support the proposed functional form of the entrainment relationship, and also the role of the pressure force in the jet deflection dynamics. Third, the observed behavior of the merging process from different types of multiport diffuser discharges in both stagnant and flowing ambient conditions and with stratification appears well predicted with the CorJet formulation. Fourth, a number of spatial limits of applicability, relating to terminal layer formation in stratification or transition to passive diffusion in a turbulent ambient shear flow, have been proposed. In sum, the CorJet integral model appears to provide a mechanistically E-mail: jirka@uka.de 44 GERHARD H. JIRKA sound, accurate and reliable representation of complex buoyant jet mixing processes, provided the condition of an unbounded receiving fluid is satisfied.

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Section: Multiport Diffuser Flows In Ambient Current Merging Of Multimentioning

confidence: 79%

Integral Model for Turbulent Buoyant Jets in Unbounded Stratified Flows Part 2: Plane Jet Dynamics Resulting from Multiport Diffuser Jets

2006

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“…For long multiport ocean outfall diffusers, F is one of the most important parameters governing the dynamics and mixing of the flow in the near field. Experiments on diffusers in both unstratified [9,10] and stratified [6,11,12] flows show that for Froude numbers less than about 0.1, the effect of the current on dilution is negligible. As the current speed is increased only slightly ( 0.1) F ≈ the upstream layer is expelled and all of the flow is swept downstream.…”

Section: Modeling Resultsmentioning

confidence: 94%

“…These experiments incorporate the most important hydrodynamic aspects of ocean outfalls, including the effects of arbitrary current speed and direction (including parallel currents), stratification, port spacing, source momentum flux, discharges from both sides of the diffuser and the resulting merging of the plumes from both sides, reentrainment and additional mixing in the spreading layer, direct plume impingement in parallel currents, and lateral gravitational spreading [8]- [12]. In addition to the laboratory data, the model has been validated against other data, including data from the field tracer and laboratory experiments for the San Francisco outfall [13], from the field tests in the Whites Point, Los Angeles outfall [14] and in the Sand Island, Hawaii outfall [15], and more recently from the field tracer of the Boston outfall [16].…”

Section: Modeling Resultsmentioning

confidence: 99%

Foz do Arelho outfall plume predictive study

Ramos

Carvalho²

2008

Oceans 2008

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A seawater quality monitoring program for Foz do Arelho outfall has already started in May 2006 to evaluate the background seawater quality around the vicinity of the sea outfall and to follow the impacts of wastewater discharge in the area. Seven monitoring campaigns were already performed between 2006-2007 in which CTD and ADCP measurements were obtained in the vicinity of the wastewater discharge. Predictions of the plume behavior for several times of the year were obtained using a near field model with the monitoring data as input. The plume behavior was mostly influenced by density stratification. During stratified conditions the plume was trapped with dilutions always above 270 to 1. During unstratified conditions the plume was surfacing with dilutions above always 375 to 1. It is concluded that the outfall is behaving as expected.

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“…Depending on the strength of seawater stratification, currents, and other variables, the horizontal spreading layer may be submerged and will not be visible on the water surface. If the receiving waters are homogeneous or weakly stratified, the plumes will reach the surface and spread horizontally away from the source (Tian et al 2004a, b;Daviero and Roberts 2006;Tian et al 2006;Hunt et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Comparing the performance of geostatistical models with additional information from covariates for sewage plume characterization

Monego

Ribeiro

Ramos

2014

Environ Sci Pollut Res

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In this work, kriging with covariates is used to model and map the spatial distribution of salinity measurements gathered by an autonomous underwater vehicle in a sea outfall monitoring campaign aiming to distinguish the effluent plume from the receiving waters and characterize its spatial variability in the vicinity of the discharge. Four different geostatistical linear models for salinity were assumed, where the distance to diffuser, the west-east positioning, and the south-north positioning were used as covariates. Sample variograms were fitted by the Matèrn models using weighted least squares and maximum likelihood estimation methods as a way to detect eventual discrepancies. Typically, the maximum likelihood method estimated very low ranges which have limited the kriging process. So, at least for these data sets, weighted least squares showed to be the most appropriate estimation method for variogram fitting. The kriged maps show clearly the spatial variation of salinity, and it is possible to identify the effluent plume in the area studied. The results obtained show some guidelines for sewage monitoring if a geostatistical analysis of the data is in mind. It is important to treat properly the existence of anomalous values and to adopt a sampling strategy that includes transects parallel and perpendicular to the effluent dispersion.

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Marine Wastewater Discharges from Multiport Diffusers. IV: Stratified Flowing Water

Cited by 22 publications

References 18 publications

Integral Model for Turbulent Buoyant Jets in Unbounded Stratified Flows Part 2: Plane Jet Dynamics Resulting from Multiport Diffuser Jets

Integral Model for Turbulent Buoyant Jets in Unbounded Stratified Flows Part 2: Plane Jet Dynamics Resulting from Multiport Diffuser Jets

Foz do Arelho outfall plume predictive study

Comparing the performance of geostatistical models with additional information from covariates for sewage plume characterization

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