Effects of vegetation on turbulent flow structure in groyne fields

Sukhodolov, Alexander N.; Sukhodolova, Tatiana A.; Krick, Julian

doi:10.1080/00221686.2016.1211183

Cited by 19 publications

(18 citation statements)

References 26 publications

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“…This is because of its stable hydraulic regime during the summer and midautumn seasons, when the branch is barred by a gravel bar from the main river and the water is supplied only by perennial groundwater springs. This river reach was previously used for field experiments examining the dynamics of fluvial wakes and the effects of vegetation on the hydrodynamics of groyne fields (Sukhodolov & Sukhodolova, ; Sukhodolov, Sukhodolova, & Krick, ).…”

Section: Field Experimentsmentioning

confidence: 99%

“…The survey pole was vertically aligned by a bubble level and the prism of the target was manually adjusted toward the direction of the total station, which was located less than 30 m away from the target. These precautions ensure the accuracy of free surface measurements within 1 mm (Sukhodolov, Krick, et al, ; Sukhodolov, Sukhodolova, & Krick, ).…”

Section: Field Experimentsmentioning

confidence: 99%

“…The topography of the free surface was surveyed for each experimental run using a method similar to that developed by Biron et al (), though without prolonged repetitions to assess the magnitude of fluctuations (Sukhodolov, Krick, et al, ; Sukhodolov, Sukhodolova, & Krick, ). Free surface elevations were sampled with a hooked gauge and a total station on a mesh of irregular locations.…”

Section: Field Experimentsmentioning

confidence: 99%

“…Turbulence is another aspect in confluence research that has gained interest in recent decades. The capability of measuring nearly instantaneous velocity fluctuations under field and laboratory conditions and to model flow dynamics with eddy resolving numerical methods has fuelled investigations of turbulence at confluences (Biron et al, , ; Bradbrook et al, ; Constantinescu, ; Rhoads & Sukhodolov, ; Sukhodolov et al, ; Sukhodolov et al, ; Sukhodolov & Rhoads, ). Observations in the field have highlighted the importance of several different types of vortical structures, lateral flapping of the mixing interface, and periodic upwelling (Biron et al, ; Bradbrook, Lane, Richards, Biron, & Roy, ; Constantinescu et al, ; Constantinescu et al, ; Rhoads & Sukhodolov, ).…”

Section: Introductionmentioning

confidence: 99%

“…Testing of the hypothesis involved an extensive experimental program. The design of this program exploits a recent methodology for carrying out controllable experiments in field‐scale facilities (Sukhodolov, ; Sukhodolov, ; Sukhodolov et al, ; Sukhodolov, Sukhodolova, & Krick, ). This provides a large width‐to‐depth ratio for the model, thereby enabling spatial separation between helical flow and small‐scale secondary motions and ensures that the final results will be free of scaling problems.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Dynamics of Flow at Concordant Gravel Bed River Confluences: Effects of Junction Angle and Momentum Flux Ratio

Sukhodolov

Sukhodolova

2019

JGR Earth Surface

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Although the dynamics of secondary flow at river confluences have received considerable attention, a lack of theoretical insight in exploratory field and experimental research has led to different conclusions about the mechanisms driving these dynamics. This study revisits the problem of secondary flow at confluences by examining responses of the flow to controllable variations in curvature of flow trajectories in a series of field‐based experiments. The experiments were performed in a physical model designed to eliminate the influence of bed morphology, while using a large width‐to‐depth ratio to enable proper identification of flow structures at different scales. The results show that no secondary flow is detectable in runs with parallel merging flows irrespective of the momentum ratio. In runs with converging channels the secondary flow is represented by large‐scale motions consisting either of a pair of counterrotating helixes or a single helix depending on the momentum ratio. Comparison of scaled measured and theoretically predicted vertical profiles of lateral velocity shows that the helical secondary flow is primarily driven by the curvature of flow trajectories. This study also indicates that small‐scale secondary motions that have the same sense of rotation as the large‐scale helixes may develop in the immediate margins of the mixing interface. Differing only slightly from the flow depth in size, they are manifested by local upwelling within the large‐scale secondary motions. Several reasons to believe that interactions of large‐scale motions with opposing sense of rotation drive these small‐scale secondary flow cells are discussed in the paper.

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Section: Field Experimentsmentioning

confidence: 99%

Section: Field Experimentsmentioning

confidence: 99%

Section: Field Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Dynamics of Flow at Concordant Gravel Bed River Confluences: Effects of Junction Angle and Momentum Flux Ratio

Sukhodolov

Sukhodolova

2019

JGR Earth Surface

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Flow behaviour in a multi‐layered vegetated floodplain region of a compound channel

Barman

Kumar

2022

Ecohydrology

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Riparian vegetation plays a crucial role in determining the flow behaviour in the channel. The effect of flow on the slope and main channel varies based on the size, type, and density of floodplain vegetation in a compound channel. Though real field vegetation distribution is non‐uniform, most studies mainly concentrate on uniformly distributed vegetation with fixed vegetation height. This paper attempts to address this issue through laboratory studies as it was not explored properly. Flow properties like velocity, Reynolds shear stress, turbulence intensities, and turbulent kinetic energy behave differently in heterogeneous vegetated channel compared with the homogeneous vegetated channel. These flow properties in the slopes and main channel section are more pronounced for uniformly distributed vegetation than non‐uniform distribution. The multi‐layered/varying vegetation height showed higher velocity, turbulent intensity, and turbulent kinetic energy than single‐layered/constant vegetation height on slopes and main channel sections. Integral scales (Taylor and Euler) analysis showed greater magnitude for uniform multi‐layered vegetation than non‐uniform multi‐layered vegetation. Further, the study of octant analysis reveals that internal outward and internal inward interaction events dominate the slope floodplain interaction section, which is not seen in no‐vegetation cases. These studies give a better perspective to understand flow in heterogenous vegetation and move closer to real field scenarios.

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Importance of vegetation in riverbank resilience: An experimental approach

Barman,

Kumar

2024

Earth Surf Processes Landf

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Floodplain (FP) vegetation determines the flow structures in river channels based on its shape, type, spacing and root‐soil binding capacity. The present study focuses on experimental approach to understand the role of FP vegetation in determining the flow patterns and morphological changes in the channels. Flow properties like streamwise and transverse velocity, along with secondary flow and turbulent kinetic energy, were compared between rectangular and compound channels considering partial vegetation cover. The presence and absence of dip phenomenon in the main channel (MC) of compound and rectangular channel respectively suggest that the dip phenomenon is influenced by both vegetation emergence in FPs and differential cross‐sectional depths of compound channels. The secondary flow direction in the slopes and MC of compound channel is towards the FP region which is opposite to that observed in rectangular channel where secondary flow is towards MC showing the effect of non‐uniform cross‐section of compound channels. The morphological changes were analysed by performing experiments in unsymmetrical erodible riverbank channels with bankfull condition considering artificial rigid FP vegetation (Phragmites karka) and naturally growing flexible vegetation (Oryza sativa). After more than 24 h of continuous experimental runs, the O. sativa remains intact in the soil because of development of strong root‐soil bond whereas; all the P. karka gets uprooted. The channel cross‐section in the downstream channel becomes almost uniform for P. karka, whereas differential cross‐sectional height is observed for O. sativa. This study shows that along with the shapes and size of vegetation, root‐soil binding capacity also determines the morphological changes in river channels. Furthermore, it also shows the importance of growing vegetation in the laboratory to properly simulate vegetation observed in river channels.

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Effects of vegetation on turbulent flow structure in groyne fields

Cited by 19 publications

References 26 publications

Dynamics of Flow at Concordant Gravel Bed River Confluences: Effects of Junction Angle and Momentum Flux Ratio

Dynamics of Flow at Concordant Gravel Bed River Confluences: Effects of Junction Angle and Momentum Flux Ratio

Flow behaviour in a multi‐layered vegetated floodplain region of a compound channel

Importance of vegetation in riverbank resilience: An experimental approach

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