Numerical modeling of sediment transport processes caused by deep sea mining discharges

Jankowski, Jacek; Malcherek, Andreas; Zielke, W.

doi:10.1109/oceans.1994.364208

Cited by 6 publications

(15 citation statements)

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“…The accurate computation of advection (of momentum or mass) is particularly challenging, and some hydrodynamic codes solve for advection in a separate, dedicated step using a numerical method best suited to the hyperbolic nature of the advective terms (examples include the CYTHERE-ES1 code (Benqué et al, 1982), and TELEMAC as reported by Jankowski et al (1994). A mobile-bed code driven by a hydrodynamics solver having this feature for momentum advection should logically take advantage of it for the advection of sediment particles in suspension.…”

Section: Solution Techniques and Their Applicabilitymentioning

confidence: 99%

“…Use of this simplification restricts the model's range of applicability, since the sediment processes are naturally unsteady and their effects accumulate in time, eventually affecting the flow computations. Another typical threedimensional flow modeling simplification is the assumption of a hydrostatic-pressure distribution over the depth as described in Section 15.3.3 above (Sheng, 1983; FLESCOT as reported by Onishi and Trent, 1985; TELEMAC-3D with sediment processes as reported by Jankowski et al, 1994;Lin and Falconer, 1996;Wang and Adeff, 1986; CH3D-SED as reported by Gessler et al, 1999). The hydrostatic-pressure assumption is easily violated wherever streamline curvature is significant (e.g.…”

Section: Assessment Of Conceptual Bases Of Mobile-bed Modelsmentioning

confidence: 99%

“…the twodimensional Argos Modeling System as described by Usseglio-Polatera and Cunge, 1985; the three-dimensional FLESCOT model of Onishi and Trent, 1985), and some not including bed changes (e.g. the three-dimensional models of Sheng, 1983;Olsen et al, 1999; TELEMAC-3D with sediment processes as described by Jankowski et al, 1994). The three-dimensional model of Lin and Falconer (1996) includes both bedload and suspended-sediment transport, but does not include bed elevation changes.…”

Section: Assessment Of Conceptual Bases Of Mobile-bed Modelsmentioning

confidence: 99%

“…(15.7.4) is derived from the suspended-sediment computations themselves. This approach was used in models described by Shimizu et al (1990), Spasojevic andHolly (1990a, 1990b), Spasojevic and Holly (1993), Jankowski et al (1994), Minh Duc et al (1998), Rodi (2000), and Wu et al (2000). As an extension to this approach, some researchers (e.g.…”

Section: Imposition Of the Near-bed Sediment Exchangementioning

confidence: 99%

“…As an extension to this approach, some researchers (e.g. Jankowski et al (1994)) have proposed introduction of a probability factor into the deposition flux in Eq. (15.7.4) to account for the possibility that some near-bed sediment particles subjected to downward advection due to their fall velocity, may be resuspended without reaching the bed.…”

Section: Imposition Of the Near-bed Sediment Exchangementioning

confidence: 99%

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Two- and Three-Dimensional Numerical Simulation of Mobile-Bed Hydrodynamics and Sedimentation

Spasojevic¹,

Holly²

2008

Sedimentation Engineering

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Type of problem 2-D (depthaveraged) 3-D required ? Hydrostatic assumption in 3-D? Unsteady flow capability required? Sediment mixture capability required? Distinct treatment of bedload/ suspended load processes? Grid requirements Turbulence model requirements Bed layering capability required? Required Generally not acceptable, since vertical Generally not necessary Required unless sediments are Required in most alluvial rivers Unstructured grid usually High level turbulence modeling Generally not necessary unless Spaso (2001 and M 12 deposition patterns, as input to the design process. Boundary effects are ubiquitous, and are naturally accommodated by three-dimensional modeling. Unless there are strong vertical accelerations near the inlet or the outlet, the hydrostatic pressure assumption may be adequate. Unsteady flow dynamics are generally not relevant for continuous-flow sedimentation basins, so steady-flow models to determine sedimentation rates may be quite appropriate. Unless the inflowing sediment is truly of uniform size, it is generally necessary that the modeling accommodate differential particle sizes, especially since this can have a direct bearing on the longitudinal deposition patterns in the sedimentation basin. To the extent that re-entrainment of deposited sediments in the basin is not an issue, it may not be necessary for the model to accommodate bedload processes and their exchanges with the water column. However if possible re-entrainment near the outlet is under study, it may be necessary to include a full representation of bedload dynamics and exchange with the water column. Since settling basins tend to have regular geometric shapes, a simple Cartesian structured grid may be sufficient. Since the diffusive transport of suspended sediments entering the basin can be an important factor in its design, it is important for the model to include at least a one-equation model for turbulence in the horizontal plane. Bed layering is of importance only if sediment reentrainment in flushing operations is anticipated, and then only if significant stratification of sediment sizes is expected. An example of a model study of sedimentation basins is that of Olsen and Skoglund (1994). 15.2.4 Riverbend dynamics and training works Three-dimensional modeling must be used for the study of mobile-bed processes in riverbends and around their associated training works (bendway weirs, spur dikes, etc.). One-dimensional models simply cannot resolve the detailed interaction between flow and sediment within the cross section. Two-dimensional depth-averaged models cannot normally resolve the secondary currents that are an essential part of this process.

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Section: Solution Techniques and Their Applicabilitymentioning

confidence: 99%