عنوان مقاله [English]
Application of aggregate coarse rockfill in hydraulic structures is increasing due to their special properties and is imperative due to its importance and their specific characteristics. Accurate investigation of the flow properties through coarse materials in order to determine hydraulic parameters is one of the most important necessities considering high application such media in civil works. On the other hands, there is less works about transitional flow through coarse materials. In order to study the flow behavior through granular materials a packed column test was built. Some experiments have done on three samples of rounded particles with average size of 10.348mm, 12.127mm and 17.785mm and seepage flow and upstream and downstream heads were recorded in a certain intervals. By using some calculating and depicting some graphs, their behaviors have evaluated. Using the relationship of flow velocity- hydraulic gradient, it was fund that such relationship is non-linear and this is a strong criteria confirming non-Darcy flow. The evaluating of results of this study by statistical indexes and its comparison by Ergun (1952), Kovacs (1981) and Sidiropoulou et al (2007) relationships showed that the relation of Sidiropoulou et al (2007) is more accurate than the other equations. The result of Reynolds number-friction factor curves has shown that with increasing the grain size diameter, friction factor is decreased and Reynolds number is increased.