Modeling depth‐averaged streamwise velocity in a channel with one‐line emergent vegetation patches

2021 ◽  
Author(s):  
Dian Li ◽  
Wenxin Huai ◽  
Mengyang Liu
Keyword(s):  
Streamwise Velocity ◽  
Emergent Vegetation ◽  
Vegetation Patches

Impacts of turbulent flow over a channel bed with a vegetation patch on the incipient motion of sediment

2018 ◽  
Vol 45 (9) ◽  
pp. 803-816
Author(s):  
Reza Shahmohammadi ◽  
Hossein Afzalimehr ◽  
Jueyi Sui
Keyword(s):  
Experimental Study ◽  
Reynolds Stress ◽  
Streamwise Velocity ◽  
Stress Pattern ◽  
Submerged Vegetation ◽  
Incipient Motion ◽  
Vegetation Patch ◽  
Motion Process ◽  
Velocity Turbulence ◽  
Vegetation Patches

In this experimental study, the effect of a submerged vegetation patch with individual plants on the incipient motion of sediment has been examined. Results showed that a vegetation patch in the channel bed affected the incipient motion process of sediment and resulted in significant impacts on flow velocity, turbulence intensities, turbulent kinetic energy, and Reynolds stress distribution. The presence of vegetation patches completely change vertical distribution of velocity and Reynolds stress pattern and leads to negative Reynolds stress values in zones with negative velocity gradient. In the presence of a vegetation patch, threshold cross-averaged streamwise velocity is 20% smaller than that without vegetation, but because of the occurrence of the preferential path around the sheath section, the near-bed streamwise velocity is the same as without vegetation. Also, vegetation increases turbulence intensity, thus encouraging sediment motion. In the presence of a vegetation patch, the Shields parameter is, on average, one and half times that of without vegetation over the bed.

scholarly journals Water-Worked Gravel Bed: State-of-the-Art Review

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 694 ◽  
Author(s):  
Ellora Padhi ◽  
Subhasish Dey ◽  
Venkappayya R. Desai ◽  
Nadia Penna ◽  
Roberto Gaudio
Keyword(s):  
State Of The Art ◽  
Flow Characteristics ◽  
Streamwise Velocity ◽  
Secondary Currents ◽  
Gravel Bed ◽  
Natural Stream ◽  
Art Research ◽  
The Comparative Study ◽  
Water Work

In a natural gravel-bed stream, the bed that has an organized roughness structure created by the streamflow is called the water-worked gravel bed (WGB). Such a bed is entirely different from that created in a laboratory by depositing and spreading gravels in the experimental flume, called the screeded gravel bed (SGB). In this paper, a review on the state-of-the-art research on WGBs is presented, highlighting the role of water-work in determining the bed topographical structures and the turbulence characteristics in the flow. In doing so, various methods used to analyze the bed topographical structures are described. Besides, the effects of the water-work on the turbulent flow characteristics, such as streamwise velocity, Reynolds and form-induced stresses, conditional turbulent events and secondary currents in WGBs are discussed. Further, the results form WGBs and SGBs are compared critically. The comparative study infers that a WGB exhibits a higher roughness than an SGB. Consequently, the former has a higher magnitude of turbulence parameters than the latter. Finally, as a future scope of research, laboratory experiments should be conducted in WGBs rather than in SGBs to have an appropriate representation of the flow field close to a natural stream.

scholarly journals Sediment transport and roughness coefficients generated by flexible vegetation patches in the emergent and submerged conditions in a semiarid alluvial open-channel

2021 ◽  
Vol 125 ◽  
pp. 107472
Author(s):  
Douglas Monteiro Cavalcante ◽  
Maria Tatiane Leonardo Chaves ◽  
Gabriella Moreira Campos ◽  
José Ramon Barros Cantalice ◽  
Genival Barros Junior
Keyword(s):  
Sediment Transport ◽  
Open Channel ◽  
Flexible Vegetation ◽  
Vegetation Patches ◽  
Submerged Conditions

scholarly journals Functional strategies and distribution of climbing plant communities in different vegetation patches in a subtropical dry forest, central Argentina

2017 ◽  
Vol 12 (1) ◽  
pp. 23-33 ◽  
Author(s):  
María Cecilia Ferrero ◽  
Sebastián R Zeballos ◽  
Juan I Whitworth-Hulse ◽  
Melisa A Giorgis ◽  
Diego E Gurvich
Keyword(s):  
Plant Communities ◽  
Dry Forest ◽  
Central Argentina ◽  
Climbing Plant ◽  
Vegetation Patches
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