Laboratory Investigation of Non-Darcy Flow through Rounded Porous Materials

Application of aggregate coarse rockfill in hydraulic structures is increasing due to their special ýproperties and is imperative due to its importance and their specific characteristics. Accurate ýinvestigation of the flow properties through coarse materials in order to determine hydraulic ýparameters is one of the most important necessities considering high application such media in civil ýworks. On the other hands, there is less works about transitional flow through coarse materials. In ýorder to study the flow behavior through granular materials a packed column test was built. Some ýexperiments have done on three samples of rounded particles with average size of 10.348mm, ýý12.127mm and 17.785mm and seepage flow and upstream and downstream heads were recorded in ýa certain intervals. By using some calculating and depicting some graphs, their behaviors have ýevaluated. Using the relationship of flow velocity- hydraulic gradient, it was fund that such ýrelationship is non-linear and this is a strong criteria confirming non-Darcy flow. The evaluating of ýresults of this study by statistical indexes and its comparison by Ergun (1952), Kovacs (1981) and ýSidiropoulou et al (2007) relationships showed that the relation of Sidiropoulou et al (2007) is more ýaccurate than the other equations. The result of Reynolds number-friction factor curves has shown ýthat with increasing the grain size diameter, friction factor is decreased and Reynolds number is ýincreased.ý