Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigation
The present study aims to focus the turbulent flow characteristics over arrays of submerged boulders in a gravel bed stream. Round shaped boulders of diameter, Dc = 6 cm were staggered over a gravel bed stream (d50 = 4 cm) with varying boulder-to-boulder spacing and the flows over the arrays were st...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Sciendo
2023-09-01
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| Series: | Journal of Hydrology and Hydromechanics |
| Subjects: | |
| Online Access: | https://doi.org/10.2478/johh-2023-0016 |
| _version_ | 1827866205175676928 |
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| author | Datta Akash Das Ratul Majumder Mrinmoy |
| author_facet | Datta Akash Das Ratul Majumder Mrinmoy |
| author_sort | Datta Akash |
| collection | DOAJ |
| description | The present study aims to focus the turbulent flow characteristics over arrays of submerged boulders in a gravel bed stream. Round shaped boulders of diameter, Dc = 6 cm were staggered over a gravel bed stream (d50 = 4 cm) with varying boulder-to-boulder spacing and the flows over the arrays were studied experimentally. The flow measurements were carried out by an acoustic Doppler velocimeter and the double averaging methodology (DAM) was applied. The results of large spacing boulder array reveals near-bed velocity deficit within 1Dc upstream to 5Dc downstream of the boulder and no influence on the approaching velocity was observed after 5Dc corroborating the recovery of boundary layer. In case of medium and small spacing boulder array, the velocity deficit is significant at all locations. The shear stress distributions depict development of high and low bed shear stresses causing redistributions of the local bed shear stress. The higher magnitude of shear stress is observed at the boulder crest whereas; the secondary peak near the gravel bed crest is attributed to the skin shear stress on the individual boulder. Moreover, the present research contributes to our understanding that the boulder array on a rough bed stream leads to higher turbulent intensity at the boulder crest level. |
| first_indexed | 2024-03-12T15:00:38Z |
| format | Article |
| id | doaj.art-970e0ed7951c46f5912016e448e33598 |
| institution | Directory Open Access Journal |
| issn | 1338-4333 |
| language | English |
| last_indexed | 2024-03-12T15:00:38Z |
| publishDate | 2023-09-01 |
| publisher | Sciendo |
| record_format | Article |
| series | Journal of Hydrology and Hydromechanics |
| spelling | doaj.art-970e0ed7951c46f5912016e448e335982023-08-14T07:11:08ZengSciendoJournal of Hydrology and Hydromechanics1338-43332023-09-0171329330410.2478/johh-2023-0016Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigationDatta Akash0Das Ratul1Majumder Mrinmoy21Civil Engineering Department, National Institute of Technology Agartala, Agartala-799046, India.1Civil Engineering Department, National Institute of Technology Agartala, Agartala-799046, India.1Civil Engineering Department, National Institute of Technology Agartala, Agartala-799046, India.The present study aims to focus the turbulent flow characteristics over arrays of submerged boulders in a gravel bed stream. Round shaped boulders of diameter, Dc = 6 cm were staggered over a gravel bed stream (d50 = 4 cm) with varying boulder-to-boulder spacing and the flows over the arrays were studied experimentally. The flow measurements were carried out by an acoustic Doppler velocimeter and the double averaging methodology (DAM) was applied. The results of large spacing boulder array reveals near-bed velocity deficit within 1Dc upstream to 5Dc downstream of the boulder and no influence on the approaching velocity was observed after 5Dc corroborating the recovery of boundary layer. In case of medium and small spacing boulder array, the velocity deficit is significant at all locations. The shear stress distributions depict development of high and low bed shear stresses causing redistributions of the local bed shear stress. The higher magnitude of shear stress is observed at the boulder crest whereas; the secondary peak near the gravel bed crest is attributed to the skin shear stress on the individual boulder. Moreover, the present research contributes to our understanding that the boulder array on a rough bed stream leads to higher turbulent intensity at the boulder crest level.https://doi.org/10.2478/johh-2023-0016boulder arrayshear stressvelocity distributionsturbulent intensity |
| spellingShingle | Datta Akash Das Ratul Majumder Mrinmoy Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigation Journal of Hydrology and Hydromechanics boulder array shear stress velocity distributions turbulent intensity |
| title | Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigation |
| title_full | Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigation |
| title_fullStr | Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigation |
| title_full_unstemmed | Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigation |
| title_short | Influence of boulder array on the near-bed turbulent flow characteristics in a gravel bed stream - An experimental investigation |
| title_sort | influence of boulder array on the near bed turbulent flow characteristics in a gravel bed stream an experimental investigation |
| topic | boulder array shear stress velocity distributions turbulent intensity |
| url | https://doi.org/10.2478/johh-2023-0016 |
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