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Shokri Morteza,Sabour Mohammadreza 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.2
This paper aims to cast light on the coefficients of non-linear equation governing unsteady turbulent flow through coarse porousmedia commonly known as Forchheimer’s equation. Experimental pilot made use of a physical model consisting of a flume of 13 mlength, being controlled by an electro-mechanical device to create different types of flow regimes. A range of granular media with amean diameter of 7.5 mm for Small crashed (Sc) to 14 mm for Medium crashed (Mc) were packed in the flume at different runs tosimulate coarse porous media capable of sustaining turbulent flow, either unsteady or steady. Findings indicate that: coefficient of thelinear flow term decreases (47.3% and 91.9% in Sc and Mc aggregate) with increasing mean grain size, respectively. In addition,coefficient of the turbulent term-the effects of inertia forces-increases (87.9% and 27.2% in Sc and Mc aggregate) with increasingmean grain size, respectively. Furthermore, coefficient of the unsteady term-local acceleration term in the Forchheimer’s equationshowsa rapid increase (146.9% in Sc and 125.6% in Mc) with increasing velocity. Moreover, the nature of hydraulic gradient (i)variations versus Reynolds number (Re) - which were plotted for all sets of observations-confirms the existence of turbulentconditions in most experiments. Finally, the head losses and contribution of above-mentioned terms to the pressure drop was quiteanalyzed.