Flow patterns in an open channel confluence with a small ratio of main channel to tributary discharge

Schindfessel, Laurent; Creëlle, Stéphan; Boelens, Thomas; Mulder, Tom De

doi:10.1201/b17133-134

Cited by 4 publications

(9 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, the downstream water level is constant, and hence the downstream Froude number Frd is constant as well, equalling 0.05. Although the Froude number is small compared to other laboratory experiments (see overview in [12]), the current value is in the typical range for lowland rivers [19]. As expected for such low subcritical flows, measurements by means of ultrasonic water level sensors show that the variation in the water level over the confluence is negligible.…”

Section: Laboratory Experiments For Numerical Model Validationmentioning

confidence: 86%

“…Eventually, the useful image recordings have a length of about 3 min. By using the PTV technique, it is possible to measure the surface velocities with a very high spatial resolution, providing better results than the particle image velocimetry technique adopted in preliminary experiments reported in [12].…”

Section: Laboratory Experiments For Numerical Model Validationmentioning

confidence: 99%

“…This is caused by flow intruding the separation zone, starting at the bed. As a consequence, the separation zone is smaller near the bed than at the top of the water column [8,[11][12][13]. Preliminary numerical simulations have indicated that this upwelling is enhanced by the presence of the chamfers [34].…”

Section: Reference Case With Moderate Discharge Ratio (Q = 025)mentioning

confidence: 99%

“…As preliminary research, Schindfessel et al [12] experimentally compared two discharge ratios, q = 0.25 and q = 0.05, in a 90° angle confluence flume and found some particularities at the small discharge ratio. The impinging tributary flow led to a recirculating eddy in the upstream channel, as well as to changes in the helicoidal cells.…”

Section: Introductionmentioning

confidence: 99%

“…From the very beginning of laboratory research on confluences, starting with Taylor [2], the ratio of incoming discharges has been recognized as a key parameter [1][2][3][4][5][6][7][8][9][10][11][12][13]. However, laboratory research was mainly performed with discharge ratios in the range of 0.1 ≲ q ≲ 0.9, at least for the case of asymmetrical confluences with a fixed concordant bed and subcritical flow throughout [12]; the type of confluence that will be further considered in this paper. In the above-mentioned equation, the discharge ratio q is defined as the ratio of upstream to downstream channel discharge (see Figure 1):…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Flow Patterns in an Open Channel Confluence with Increasingly Dominant Tributary Inflow

Schindfessel

Creëlle

Mulder

2015

Water

View full text Add to dashboard Cite

Despite the ratio of incoming discharges being recognized as a key parameter in open-channel confluence hydrodynamics, little is known about the flow patterns when the tributary provides more than 90% of the total discharge. This paper offers a systematic study of flow features when the tributary becomes increasingly dominant in a 90° confluence with a fixed concordant bed. Large-eddy simulations are used to investigate the three-dimensional complex flow patterns for three different discharge ratios. It is found that the tributary flow impinges on the opposing bank when the tributary flow becomes sufficiently dominant, causing a recirculating eddy in the upstream channel of the confluence, which induces significant changes in the incoming velocity distribution. Moreover, it results in stronger helicoidal cells in the downstream channel, along with zones of upwelling flow. In turn, the changed flow patterns also influence the mixing layer and the flow recovery. Finally, intermittent events of stronger upwelling flow are discerned. Improved understanding of flow patterns at confluences where the tributary is dominant is applicable to both engineering and earth sciences.

show abstract

Section: Laboratory Experiments For Numerical Model Validationmentioning

confidence: 86%

Section: Laboratory Experiments For Numerical Model Validationmentioning

confidence: 99%

Section: Reference Case With Moderate Discharge Ratio (Q = 025)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Flow Patterns in an Open Channel Confluence with Increasingly Dominant Tributary Inflow

Schindfessel

Creëlle

Mulder

2015

Water

View full text Add to dashboard Cite

show abstract

The flow Confluence of river systems of the Pskem and Koksu river basins

Shaazizov

2021

E3S Web Conf.

View full text Add to dashboard Cite

In the Bostanlyk district of the Tashkent region, there are high-mountain breakthrough lakes located in the Pskem and Koksu rivers basin, which pose a particular danger to the downstream territories. The river system of the basins of the Pskem and Koksu rivers located in the Tashkent region is characterized by the presence of many nodes of a confluence of tributaries that form the hydrographic network of the basins of the high-mountain rivers under consideration. In the event of man-made and natural emergencies, a breakthrough wave can form on high-mountain outburst-hazardous lakes. The main purpose of these studies is to develop a method for the hydraulic calculation to determine the depths of flows in the confluence nodes. Based on the use of the law of conservation of momentum, a model and method for calculating the junction of open water streams have been developed. To determine the depth h2 in the main channel after the confluence point, we recommend using the well-known hydraulic methods for determining the depth of water in open channels. Determination of the depths h1 and h0 of the main flow and inflow, respectively, can be analytically obtained based on the obtained dependences (9) and (10).

show abstract

How Different Cross-Sectional Shapes Influence the Separation Zone of an Open-Channel Confluence

2017

View full text Add to dashboard Cite

Flow patterns in an open channel confluence with a small ratio of main channel to tributary discharge

Cited by 4 publications

References 1 publication

Flow Patterns in an Open Channel Confluence with Increasingly Dominant Tributary Inflow

Flow Patterns in an Open Channel Confluence with Increasingly Dominant Tributary Inflow

The flow Confluence of river systems of the Pskem and Koksu river basins

How Different Cross-Sectional Shapes Influence the Separation Zone of an Open-Channel Confluence

Contact Info

Product

Resources

About