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
Author : E.P. KOSTIDOU & G.C. CHRISTODOULOU
ABSTRACT
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
discussed.
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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