Characteristics of Shallow Flows in a Vegetated Pool—An Experimental Study
Pools are often observed in gravel-bed rivers, together with the presence of vegetation patches. In the present study, a conceptual model of a gradual varied flow with both convective deceleration and acceleration flow sections has been constructed in a flume to study turbulent flow structures. Vege...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-01-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/15/1/205 |
| _version_ | 1797431066431062016 |
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| author | Parsa Parvizi Hossein Afzalimehr Jueyi Sui Hamid Reza Raeisifar Ali Reza Eftekhari |
| author_facet | Parsa Parvizi Hossein Afzalimehr Jueyi Sui Hamid Reza Raeisifar Ali Reza Eftekhari |
| author_sort | Parsa Parvizi |
| collection | DOAJ |
| description | Pools are often observed in gravel-bed rivers, together with the presence of vegetation patches. In the present study, a conceptual model of a gradual varied flow with both convective deceleration and acceleration flow sections has been constructed in a flume to study turbulent flow structures. Vegetation patches with extended canopies were planted in the pool sections in order to increase the thickness of the boundary layer inside the inner zone. The effects of different flows (namely decelerating, uniform and accelerating flows) along an artificial pool on flow velocity, shear stress and bursting events have been investigated. In addition, due to the occurrence of secondary currents in shallow streams, the characteristics of turbulent shallow flow have been investigated along two axes that are parallel to the sidewall of the flume. The results showed that the application of the log law should be used with care to estimate shear velocity along a pool with a vegetated bed. The presence of a vegetation patch causes an increase in Reynolds shear stress, especially along the entrance section of the pool where the flow decelerates. The results of the quadrant analysis reveal that the sweep and ejection events have the most dominant influence over the vegetation patch in the pool; however, the contributions of outward and inward events increase near the bed, especially in the entrance section of the pool where the flow is decelerating. The distribution of stream-wise RMS of turbulence intensity along the pool generally presents a convex shape. |
| first_indexed | 2024-03-09T09:36:32Z |
| format | Article |
| id | doaj.art-33082aa93900440e83184e6e88114596 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-09T09:36:32Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-33082aa93900440e83184e6e881145962023-12-02T01:16:36ZengMDPI AGWater2073-44412023-01-0115120510.3390/w15010205Characteristics of Shallow Flows in a Vegetated Pool—An Experimental StudyParsa Parvizi0Hossein Afzalimehr1Jueyi Sui2Hamid Reza Raeisifar3Ali Reza Eftekhari4Department of Hydraulic, Isfahan University of Technology, Isfahan 8415683111, IranDepartment of Civil Engineering, Iran University of Science and Technology, Tehran 1311416846, IranSchool of Engineering, University of Northern British Columbia, Prince George, BC V2N 4Z9, CanadaDepartment of Civil Engineering, Iran University of Science and Technology, Tehran 1311416846, IranDepartment of Civil Engineering, Iran University of Science and Technology, Tehran 1311416846, IranPools are often observed in gravel-bed rivers, together with the presence of vegetation patches. In the present study, a conceptual model of a gradual varied flow with both convective deceleration and acceleration flow sections has been constructed in a flume to study turbulent flow structures. Vegetation patches with extended canopies were planted in the pool sections in order to increase the thickness of the boundary layer inside the inner zone. The effects of different flows (namely decelerating, uniform and accelerating flows) along an artificial pool on flow velocity, shear stress and bursting events have been investigated. In addition, due to the occurrence of secondary currents in shallow streams, the characteristics of turbulent shallow flow have been investigated along two axes that are parallel to the sidewall of the flume. The results showed that the application of the log law should be used with care to estimate shear velocity along a pool with a vegetated bed. The presence of a vegetation patch causes an increase in Reynolds shear stress, especially along the entrance section of the pool where the flow decelerates. The results of the quadrant analysis reveal that the sweep and ejection events have the most dominant influence over the vegetation patch in the pool; however, the contributions of outward and inward events increase near the bed, especially in the entrance section of the pool where the flow is decelerating. The distribution of stream-wise RMS of turbulence intensity along the pool generally presents a convex shape.https://www.mdpi.com/2073-4441/15/1/205shallow currentsshear velocitypoolquadrant analysisvegetation patch |
| spellingShingle | Parsa Parvizi Hossein Afzalimehr Jueyi Sui Hamid Reza Raeisifar Ali Reza Eftekhari Characteristics of Shallow Flows in a Vegetated Pool—An Experimental Study Water shallow currents shear velocity pool quadrant analysis vegetation patch |
| title | Characteristics of Shallow Flows in a Vegetated Pool—An Experimental Study |
| title_full | Characteristics of Shallow Flows in a Vegetated Pool—An Experimental Study |
| title_fullStr | Characteristics of Shallow Flows in a Vegetated Pool—An Experimental Study |
| title_full_unstemmed | Characteristics of Shallow Flows in a Vegetated Pool—An Experimental Study |
| title_short | Characteristics of Shallow Flows in a Vegetated Pool—An Experimental Study |
| title_sort | characteristics of shallow flows in a vegetated pool an experimental study |
| topic | shallow currents shear velocity pool quadrant analysis vegetation patch |
| url | https://www.mdpi.com/2073-4441/15/1/205 |
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