Application of spatiotemporal velocity method in concrete canals with vegetation patch

Journal of Hydrology and Hydromechanics, Journal Year: 2025, Volume and Issue: 73(1), P. 108 - 120

Published: March 1, 2025

Abstract Abstract: Understanding the interaction of flow and vegetation in open canals has a great impact on better implementation environmental projects hydraulic engineering. The purpose this research is to apply spatiotemporal (spatial temporal) averaging method concrete presence patches. Therefore, research, four reaches irrigation with patches were investigated Iran. measured data includes velocity surveying. results profiles showed that log-law fits nicely near bed local values shear compared unit value extracted from double-averaged profile. comparison percentage difference between resulting each profile not significant most cases. Thus, able reflect characteristics entire conditions

Language: Английский

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Comparison of Velocity and Reynolds Stress Distributions in a Straight Rectangular Channel with Submerged and Emergent Vegetation

Water, Journal Year: 2023, Volume and Issue: 15(13), P. 2435 - 2435

Published: July 1, 2023

Vegetation in rivers and streams plays an important role preventing erosion improving bank stability. Comparison between emergent vegetation (bank vegetation) submerged vegetation, terms of velocity Reynolds stress distributions, for the same aspect ratio flow discharge, has received limited attention literature. This study investigates stress, as well log law a laboratory flume compares results different set up with sediment size but discharge. The indicate that influence on secondary currents generation is less than vegetation. In addition, application valid both cases, however, it to y/h = 0.75 (in which cover banks partly out water) 0.25 bank. For distribution presents convex form turning point. those artificial pool over low (<5) keeps almost distributions decreases point distribution. cover, location zero shear superposes maximum velocity, approaching shifting towards bed, approaches bed.

Language: Английский

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Turbulence Kinetic Energy and High-Order Moments of Velocity Fluctuations of Flows in the Presence of Submerged Vegetation in Pools

Water, Journal Year: 2023, Volume and Issue: 15(12), P. 2170 - 2170

Published: June 8, 2023

The flow in arid and semi-arid regions changes significantly during seasons, letting many vegetation patches develop different parts of rivers. In the presence aquatic plants streams, structures have resulted. When water level increases these rivers, influences turbulent structures, which may considerably change estimation key hydraulic parameters. results earlier investigations indicated that a wide range submerged non-submerged hydrodynamic features flows rivers streams. present investigation, two pools with various slopes entry exit sections were used to conduct eight independent experiment runs. addition, patch over entire pool section has been set up investigate effects on pools. effect 5 10 degrees for both entrance structure investigated. Considering aspect ratios 2.0 2.7, distributions velocity, Reynolds normal shear stresses, turbulence intensities, kinetic energy (TKE), quadrant analysis, spectral analysis studied at trailing edge along an artificial pool. Results show that, large (10 degrees), TKE distribution profiles no specific form. However, values convex-shaped pattern maximum value near bed when are small (5 degrees). showed ejections sweeps govern coherent motions geometry, entrance, validation power function compared flatbed.

Language: Английский

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Effects of Channel Width Variations on Turbulent Flow Structures in the Presence of Three-Dimensional Pool-Riffle

Sustainability, Journal Year: 2023, Volume and Issue: 15(10), P. 7829 - 7829

Published: May 10, 2023

Changes in the width of channels or rivers that have three-dimensional pool-riffle can affect key parameters river engineering and flow resistance. Understanding effect changes on structures helps to control erosion sedimentation coarse-bed better design ecological restoration projects. The present study investigates sequential its interaction with bank narrowness turbulent characteristics. For this purpose, an experimental was conducted variable fixed flume aspect ratio greater than five. results showed when decelerates (entrance pool), negative low longitudinal velocities expand as depth increases. From both sides central axis, decreased entering middle part pool reduced width. maximum turbulence intensity values, from axis towards channel bank, modes had increasing trend. In all three directions along flume, Reynolds shear stress mode were larger those one. Knowledge pattern a stream understanding velocity distribution will help engineers estimate controlling improve hydraulic models’ performance.

Language: Английский

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Turbulence Kinetic Energy and High-order Moments of Veloc-ity Fluctuations of Flows in the Presence of Submerged Vegetation in Pools

Published: May 11, 2023

In the presence of aquatic plants in streams, a variety flow structures have been reported. Re-sults earlier investigations indicated that hydrodynamic features flows rivers, and streams are influenced by wide range submerged non-submerged vegetation. pre-sent study, eight experiment runs were conducted two artificial pools built laboratory flume to assess across vegetation cover. The slopes for entrance exit sec-tions these 5 10 degrees, respectively. A patch grass covered entire pool area over gravel bed. effect stream velocity was investigated considering aspect ratios 2 2.7. Also, distributions velocity, Reynolds normal shear stresses, turbulence intensities, turbulent kinetic energy (TKE), higher-order mo-ments fluctuations investigated. By means quadrant analysis, it is found skewness coefficients profiles significant parameters evaluate. Based on values bursting processes, along section with smaller slope, contribution sweep motion occurs more restricted zone above canopy, this im-plies ejection higher slope. Immediately dominant process events. Whereas, at upstream boundary patch, an outward slightly pos-itive value occurs; around downstream isotropic appears Over canopy pool, less mixing eddies result lower stress values, thus becomes weak (TKE). Because shallow channel ratio than five availability vertical non-zero ve-locity components, secondary currents become stronger channel. Consequently, there divergence from linear dispersion stress.

Language: Английский

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Fluvial Hydraulics in the Presence of Vegetation in Channels

Water, Journal Year: 2023, Volume and Issue: 15(16), P. 2907 - 2907

Published: Aug. 11, 2023

In many semi- and arid regions, water does not flow from middle spring to early fall, leading the development of vegetation patches with irregular distribution on channel beds banks [...]

Language: Английский

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