Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam Reservoir
In reservoir of dams, especially near the dam body, the cohesive fine sediments are deposited mainly. The mechanical behavior of these sediments is largely controlled by the interparticle attraction caused by electrostatic and physiochemical forces. these properties cause the stickiness and accumula...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | fas |
| Published: |
Shahid Chamran University of Ahvaz
2018-06-01
|
| Series: | علوم و مهندسی آبیاری |
| Subjects: | |
| Online Access: | http://jise.scu.ac.ir/article_13671_5edf5d1920ed773f6487f0fc6d204f20.pdf |
| _version_ | 1818446751502172160 |
|---|---|
| author | Mahnaz Shadorvan Babak Lashkar-Ara Hesam Seyed kaboli |
| author_facet | Mahnaz Shadorvan Babak Lashkar-Ara Hesam Seyed kaboli |
| author_sort | Mahnaz Shadorvan |
| collection | DOAJ |
| description | In reservoir of dams, especially near the dam body, the cohesive fine sediments are deposited mainly. The mechanical behavior of these sediments is largely controlled by the interparticle attraction caused by electrostatic and physiochemical forces. these properties cause the stickiness and accumulation of clay particles and formation of dense masses called flocs, which is sometimes referred to as flocculation. flocculation is influenced by several factors including salinity, flow regime, sediment concentration and organic matter. Flocculation is the most important factor that makes the settling, fall velocity and transfer of cohesive sediment considerably more complex and dynamic than non-cohesive sediments. In order to determine the relations governing cohesive sediments, the physical characteristics and behavior of these sediments should be identified. The terminal settling velocity of sedimentary particles in liquids, called particle fall velocity, is one of the most important properties in determining the physical properties of sediments caused transfer, deposition and consolidation. The fall velocity of cohesive sediments is influenced by many factors, including salinity, initial particle size, turbulence, temperature of water, and suspended sediment concentration. <br />McLaughlin (1959) provided a method for measuring the fall velocity of particle (ω) in stillwater, using a settling cylinder with 10 cm diameter and less than 1 meter height and established a differential formula based on its research as follows: <br /><br />d(wC)/dz+dC/dt=0 (1) <br /><br />Fathi Moghadam et al (2011) studied the settling properties of the cohesive sediments in the Dez Dam reservoir. They concluded that particles for all concentrated samples and in all depths reached to their maximum fall velocity approximately at the same time (15 minutes after starting the test). The lower concentration samples appeared to have higher maximum fall velocities than the higher concentration samples, but for a shorter duration. |
| first_indexed | 2024-12-14T19:52:42Z |
| format | Article |
| id | doaj.art-7738363762e54d0db6ed60d0f7dc61b6 |
| institution | Directory Open Access Journal |
| issn | 2588-5952 2588-5960 |
| language | fas |
| last_indexed | 2024-12-14T19:52:42Z |
| publishDate | 2018-06-01 |
| publisher | Shahid Chamran University of Ahvaz |
| record_format | Article |
| series | علوم و مهندسی آبیاری |
| spelling | doaj.art-7738363762e54d0db6ed60d0f7dc61b62022-12-21T22:49:22ZfasShahid Chamran University of Ahvazعلوم و مهندسی آبیاری2588-59522588-59602018-06-0141221122410.22055/jise.2018.22358.160113671Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam ReservoirMahnaz Shadorvan0Babak Lashkar-Ara1Hesam Seyed kaboli2M.Sc. Student, Department of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran.Assistant Professor, Department of Civil Engineering, Jundi-Shapur University of Technology, Dezful, IranAssistant Professor, Department of Civil Engineering, Jundi-Shapur University of Technology, Dezful, IranIn reservoir of dams, especially near the dam body, the cohesive fine sediments are deposited mainly. The mechanical behavior of these sediments is largely controlled by the interparticle attraction caused by electrostatic and physiochemical forces. these properties cause the stickiness and accumulation of clay particles and formation of dense masses called flocs, which is sometimes referred to as flocculation. flocculation is influenced by several factors including salinity, flow regime, sediment concentration and organic matter. Flocculation is the most important factor that makes the settling, fall velocity and transfer of cohesive sediment considerably more complex and dynamic than non-cohesive sediments. In order to determine the relations governing cohesive sediments, the physical characteristics and behavior of these sediments should be identified. The terminal settling velocity of sedimentary particles in liquids, called particle fall velocity, is one of the most important properties in determining the physical properties of sediments caused transfer, deposition and consolidation. The fall velocity of cohesive sediments is influenced by many factors, including salinity, initial particle size, turbulence, temperature of water, and suspended sediment concentration. <br />McLaughlin (1959) provided a method for measuring the fall velocity of particle (ω) in stillwater, using a settling cylinder with 10 cm diameter and less than 1 meter height and established a differential formula based on its research as follows: <br /><br />d(wC)/dz+dC/dt=0 (1) <br /><br />Fathi Moghadam et al (2011) studied the settling properties of the cohesive sediments in the Dez Dam reservoir. They concluded that particles for all concentrated samples and in all depths reached to their maximum fall velocity approximately at the same time (15 minutes after starting the test). The lower concentration samples appeared to have higher maximum fall velocities than the higher concentration samples, but for a shorter duration.http://jise.scu.ac.ir/article_13671_5edf5d1920ed773f6487f0fc6d204f20.pdfsettling columnflocculation reactionfall velocitycohesive sediment |
| spellingShingle | Mahnaz Shadorvan Babak Lashkar-Ara Hesam Seyed kaboli Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam Reservoir علوم و مهندسی آبیاری settling column flocculation reaction fall velocity cohesive sediment |
| title | Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam Reservoir |
| title_full | Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam Reservoir |
| title_fullStr | Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam Reservoir |
| title_full_unstemmed | Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam Reservoir |
| title_short | Assessment of the Cohesive Sediments Fall Velocity in Karkheh Dam Reservoir |
| title_sort | assessment of the cohesive sediments fall velocity in karkheh dam reservoir |
| topic | settling column flocculation reaction fall velocity cohesive sediment |
| url | http://jise.scu.ac.ir/article_13671_5edf5d1920ed773f6487f0fc6d204f20.pdf |
| work_keys_str_mv | AT mahnazshadorvan assessmentofthecohesivesedimentsfallvelocityinkarkhehdamreservoir AT babaklashkarara assessmentofthecohesivesedimentsfallvelocityinkarkhehdamreservoir AT hesamseyedkaboli assessmentofthecohesivesedimentsfallvelocityinkarkhehdamreservoir |