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.
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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : Equivalent roughness of artificial vegetation in subcritical flow
Equivalent roughness of artificial vegetation in subcritical flow
The paper focuses on determining the resistance characteristics of some selected artificial vegetation elements and
patterns in terms of the friction factor f and the equivalent sand roughness ks, based on laboratory experiments. Three
types of vegetation elements were used: (a) Thin rigid rods 0.5 cm in diameter and 4 cm high, always submerged; (b)
Flexible plastic tubes (20 cm high) adjusted on the same rods, which were submerged or emergent depending on the
flow rate; (c) Compound elements, consisting of rigid rods 0.8 cm in diameter and 5 cm high, bearing 3 cm diameter
spheres on top, mostly submerged. Three patterns of each type of element were investigated, at plan densities ranging
from 100 to 400 stems/m2. By measuring the free surface profiles, the Manning’s n coefficient was evaluated and
subsequently the respective friction factor f and equivalent roughness ks were determined. The results are corrected for
sidewall effects and presented in dimensionless form. Quantitative expressions are proposed relating f and ks to the
density and other geometrical parameters characteristic of the vegetation array. Comparison with previous research is
File Size : 380,387 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 19/08/2015
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