IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
Log On
About IAHRDirectoryCommitteesMy IAHRNews & JournalseLibraryeShopEventsJoin IAHRWorld CongressDonate
spacer.gif
spacer.gif eLibrary
spacer.gif eLibrary
You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : Study on the flow characteristics in embaymnet with spur dikes
Study on the flow characteristics in embaymnet with spur dikes
Author : TAKESHI TAKEMURA(1), HIROKAZU SUMI(2), TOMOAKI NAKAMURA(3), AKIRA ODA(4) & MINORU OCHIAI(5)
ABSTRACT
Spur dike, one of the hydraulic structures, is used for the purpose of preventing the erosion of the river bed or river bank
by changing the direction of flow. Sometimes embayment is formed for such as scour or deposition of sediment occurs
around the spur dikes. The embayment is used by some fishes, benthos or etc. Therefore, it is important to maintain
condition continuously in embayment, however, it is difficult. In this study, flow structures in embayment with spur dikes are
investigated using two-component electromagnetic velocimetry and flow visualization technique.
The embayment was made with two spur dikes and the aspect ratio (W/L) of it set 3 (width of embayment along
streamwise direction: W, length of spur dike cross-stream direction: L) or 5. We used four types spur dike model, two
impermeable spur dikes (Type-1), Type-1 with an impermeable flat plate 1/3B in length located along boundary between
spur dikes (Type-2), replace the impermeable spur dike to permeable one on the upstream side (Type-3) and Type-3 with
an impermeable flat plate 1/3B in length located along boundary between spur dikes (Type-4), in the experiments. In
addition, the alphabet A or B (indicating the difference in aspect ratio) added at the end of the model name. Flow
characteristics in embayment are investigated by flow velocity, momentum exchange rates between the main flow region
and in the embayment, and flow visualization.
As an experimental result, the mean flow velocity and RMSD of Type-3-A is about 1.53 times and 1.09 higher than Type-1-
A respectively. Moreover, it is confirmed that there are few large fluctuation in flow in embayment. We investigate these
four models carefully and reach a conclusion that the model Type-3-A is easy to maintain because of reduces the size of
recirculation by permeability flow velocity from spur dike at upstream side.
File Size : 519,252 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 27/08/2015
Download Now