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Air‐water flows in the presence of staggered and row boulders under macroroughness conditions
Author(s) -
Pagliara S.,
Carnacina I.,
Roshni T.
Publication year - 2010
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2009wr008834
Subject(s) - flow (mathematics) , aeration , air water , surface finish , airflow , flow conditions , mechanics , surface roughness , water flow , geology , geotechnical engineering , materials science , environmental science , engineering , composite material , mechanical engineering , physics , waste management
Free surface flow over a rough bed at steep slopes entrains large amounts of air bubbles due to the high interaction between the free surface and the bed materials. The assessment of mixed air‐water flow features in the presence of a three‐dimensional bed configuration from macroroughness to intermediate roughness conditions can hardly be accomplished with aeration models developed for smooth or stepped bed configurations. Two‐phase flow properties were measured over rough bed materials in a setup assembled at the PITLAB center at the University of Pisa, Pisa, Italy. Coarser protruding materials were incorporated over the rough bed to intensify the aeration in the mixed air‐water flow. Flow discharges ranging between 0.02 and 0.09 m 2 /s and slopes between 0.18 and 0.44 were tested. A detailed study of the air‐water inner layer and flow features over staggered and row coarser material arrangement over the base material was carried out. Results were compared with literature data on free surface flow over smooth and stepped beds.