Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence Characteristics
In this experimental study, using an ADV, experiments were performed in three different shallow water flows under hydraulically transitional flow condition to estimate the bed shear stress using turbulence characteristics. Vertical distributions of all shear and normal Reynolds stresses as well as T...
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| Format: | Article |
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MDPI AG
2022-08-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/14/16/2515 |
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| author | Reza Shahmohammadi Hossein Afzalimehr Jueyi Sui |
| author_facet | Reza Shahmohammadi Hossein Afzalimehr Jueyi Sui |
| author_sort | Reza Shahmohammadi |
| collection | DOAJ |
| description | In this experimental study, using an ADV, experiments were performed in three different shallow water flows under hydraulically transitional flow condition to estimate the bed shear stress using turbulence characteristics. Vertical distributions of all shear and normal Reynolds stresses as well as TKE were evaluated and simplified in order to estimate bed shear stress under incipient motion of four groups of sand particles. To determine bed shear stress, as the main approach, the linear portion of the −u′w′ profiles were extended towards the channel bed. The necessity of the approach of the vector addition of −u′w′ and −v′w′ in this experimental study was examined. It was found that the bed shear stress can be effectively estimated by multiplying the values of u′<sup>2</sup><sub>0</sub>, v′<sup>2</sup><sub>0</sub>, w′<sup>2</sup><sub>0</sub> and TKE<sub>0</sub> by 0.17, 0.33, 1.24 and 0.2, respectively. However, it was found that these values were slightly proportional to the shear Reynolds number. Additionally, the one-point measurement approach was assessed. The TKE method which applies all three components of Reynolds normal stresses was preferred to the u′<sup>2</sup>, v′<sup>2</sup> and w′<sup>2</sup> methods. Results showed that, u′<sup>2</sup><sub>0</sub>, v′<sup>2</sup><sub>0</sub> and w′<sup>2</sup><sub>0</sub> have values of 60.5, 31.3 and 8.2 percent of the total, respectively. |
| first_indexed | 2024-03-09T12:20:55Z |
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| id | doaj.art-813d473e95e14aac86627cb1d4bd8ed7 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-09T12:20:55Z |
| publishDate | 2022-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-813d473e95e14aac86627cb1d4bd8ed72023-11-30T22:40:32ZengMDPI AGWater2073-44412022-08-011416251510.3390/w14162515Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence CharacteristicsReza Shahmohammadi0Hossein Afzalimehr1Jueyi Sui2Department of Water Engineering, Isfahan University of Technology, Isfahan 8415683111, IranDepartment of Civil Engineering, Iran University of Science and Technology, Tehran 1684613114, IranSchool of Engineering, University of Northern British Columbia, Prince George, BC V2N 4Z9, CanadaIn this experimental study, using an ADV, experiments were performed in three different shallow water flows under hydraulically transitional flow condition to estimate the bed shear stress using turbulence characteristics. Vertical distributions of all shear and normal Reynolds stresses as well as TKE were evaluated and simplified in order to estimate bed shear stress under incipient motion of four groups of sand particles. To determine bed shear stress, as the main approach, the linear portion of the −u′w′ profiles were extended towards the channel bed. The necessity of the approach of the vector addition of −u′w′ and −v′w′ in this experimental study was examined. It was found that the bed shear stress can be effectively estimated by multiplying the values of u′<sup>2</sup><sub>0</sub>, v′<sup>2</sup><sub>0</sub>, w′<sup>2</sup><sub>0</sub> and TKE<sub>0</sub> by 0.17, 0.33, 1.24 and 0.2, respectively. However, it was found that these values were slightly proportional to the shear Reynolds number. Additionally, the one-point measurement approach was assessed. The TKE method which applies all three components of Reynolds normal stresses was preferred to the u′<sup>2</sup>, v′<sup>2</sup> and w′<sup>2</sup> methods. Results showed that, u′<sup>2</sup><sub>0</sub>, v′<sup>2</sup><sub>0</sub> and w′<sup>2</sup><sub>0</sub> have values of 60.5, 31.3 and 8.2 percent of the total, respectively.https://www.mdpi.com/2073-4441/14/16/2515bed shear stressReynolds normal stressReynolds shear stresstransitional flowturbulent kinetic energy |
| spellingShingle | Reza Shahmohammadi Hossein Afzalimehr Jueyi Sui Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence Characteristics Water bed shear stress Reynolds normal stress Reynolds shear stress transitional flow turbulent kinetic energy |
| title | Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence Characteristics |
| title_full | Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence Characteristics |
| title_fullStr | Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence Characteristics |
| title_full_unstemmed | Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence Characteristics |
| title_short | Estimation of Bed Shear Stress in Shallow Transitional Flows under Condition of Incipient Motion of Sand Particles Using Turbulence Characteristics |
| title_sort | estimation of bed shear stress in shallow transitional flows under condition of incipient motion of sand particles using turbulence characteristics |
| topic | bed shear stress Reynolds normal stress Reynolds shear stress transitional flow turbulent kinetic energy |
| url | https://www.mdpi.com/2073-4441/14/16/2515 |
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