Next Article in Journal
Cardiac Triangle Mapping: A New Systems Approach for Noninvasive Evaluation of Left Ventricular End Diastolic Pressure
Next Article in Special Issue
A Three-Dimensional Flow and Sediment Transport Model for Free-Surface Open Channel Flows on Unstructured Flexible Meshes
Previous Article in Journal
Vortex Interactions Subjected to Deformation Flows: A Review
Previous Article in Special Issue
The Past and Present of Discharge Capacity Modeling for Spillways—A Swedish Perspective
Article Menu

Export Article

Open AccessArticle
Fluids 2019, 4(1), 15; https://doi.org/10.3390/fluids4010015

Field Studies and 3D Modelling of Morphodynamics in a Meandering River Reach Dominated by Tides and Suspended Load

1
Division of Fluid and Experimental Mechanics, Luleå University of Technology, 97187 Luleå, Sweden
2
Vattenfall AB, Research and Development, Hydraulic Laboratory, 81426 Älvkarleby, Sweden
3
Resources, Energy and Infrastructure, Royal Institute of Technology, 10044 Stockholm, Sweden
*
Author to whom correspondence should be addressed.
Received: 9 December 2018 / Revised: 11 January 2019 / Accepted: 20 January 2019 / Published: 22 January 2019
(This article belongs to the Special Issue Free surface flows)
Full-Text   |   PDF [6782 KB, uploaded 22 January 2019]   |  

Abstract

Meandering is a common feature in natural alluvial streams. This study deals with alluvial behaviors of a meander reach subjected to both fresh-water flow and strong tides from the coast. Field measurements are carried out to obtain flow and sediment data. Approximately 95% of the sediment in the river is suspended load of silt and clay. The results indicate that, due to the tidal currents, the flow velocity and sediment concentration are always out of phase with each other. The cross-sectional asymmetry and bi-directional flow result in higher sediment concentration along inner banks than along outer banks of the main stream. For a given location, the near-bed concentration is 2−5 times the surface value. Based on Froude number, a sediment carrying capacity formula is derived for the flood and ebb tides. The tidal flow stirs the sediment and modifies its concentration and transport. A 3D hydrodynamic model of flow and suspended sediment transport is established to compute the flow patterns and morphology changes. Cross-sectional currents, bed shear stress and erosion-deposition patterns are discussed. The flow in cross-section exhibits significant stratification and even an opposite flow direction during the tidal rise and fall; the vertical velocity profile deviates from the logarithmic distribution. During the flow reversal between flood and ebb tides, sediment deposits, which is affected by slack-water durations. The bed deformation is dependent on the meander asymmetry and the interaction between the fresh water flow and tides. The flood tides are attributable to the deposition, while the ebb tides, together with run-offs, lead to slight erosion. The flood tides play a key role in the morphodynamic changes of the meander reach. View Full-Text
Keywords: tidal meandering river; field measurements; 3D numerical model; flow features; sediment transport; erosion-deposition patterns tidal meandering river; field measurements; 3D numerical model; flow features; sediment transport; erosion-deposition patterns
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Xie, Q.; Yang, J.; Lundström, T.S. Field Studies and 3D Modelling of Morphodynamics in a Meandering River Reach Dominated by Tides and Suspended Load. Fluids 2019, 4, 15.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Fluids EISSN 2311-5521 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top