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 m2/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.
Air-water flows in the presence of staggered and row boulders under macroroughness conditions
PAGLIARA, STEFANO;
2010-01-01
Abstract
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 m2/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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
