Experimental study of radial non-Darcy flows in coarse alluvial beds

Analysis of non-laminar flows in coarse alluvial beds have many applications in different fields such as oil and gas, civil and geology engineering. Since the Darcy equation doesn’t work for analyzing turbulent and transitional flows, we are forced to use nonlinear relationships, divided into two groups of exponential and binomial. The binomial relationship has more accuracy in a vast domain of speed variations than exponential relationship, as its validity has been confirmed through dimensional analysis and Navier- Stokes's equations. Until now, the non-Darcy flow analysis in conditions with relatively parallel flow lines, for free surface and under-pressure states, has been evaluated by many researchers. The researches carried out about the analysis of non-Darcy under pressure flow with convergent lines indicated that a) the behavior of this flow is different from the one with relatively parallel flow lines, b) the binomial relationship works well in the analysis of this flow, with a great accuracy. In this research, an experimental setup with a semi cylindrical shape with a diameter of 6 m and height of 3 m was constructed. The results of experimental research showed the behavior of radial flows with free surface differs from convergent under-pressure flow and from that of non-Darcy flow with relatively parallel streamlines.