Fadhil M.  Al-Mohammed, 
    Behaviour of Water Flow Through Monosized Gravel Media,
    Journal of Engineering and Applied Sciences,
    Volume 14,Issue 13,
    2019,
    Pages 4459-4465,
    ISSN 1816-949x,
    jeasci.2019.4459.4465,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2019.4459.4465)
    Abstract: Gravel materials are widely used in hydraulic structures such as self-spillway dams. Darcy’s law is
used in engineering applications to represent flow through soil in this case the flow will be Laminar. When
analyzing the flow through coarse porous materials such as gravel it leads to deviation in the results from
Darcy’s law because of high velocity of flow that causes a nonlinear relationship between hydraulic gradient
and bulk flow velocity. The present study aimed to investigate the behaviour of flow through monosized gravel
and to determine the effect of hydraulic gradient and gravel mean size in hydraulic conductivity under turbulent
flow condition. The porous materials used in this study were seven monosized gravel samples with diameters
ranging from -4.75+4 to -31.5+25 mm. A hydraulic conductivity test rig was constructed to measure the hydraulic
conductivity of the gravel samples. Hydraulic gradient values used to conduct the experiments ranged between
0.01 and 0.237 while the discharge values ranged between 0.0149 and 0.255 L/sec. The results showed that the
flow through monosized gravel didn’t obey Darcy’s law and a strong non-linear relationship was found
between hydraulic gradient and bulk flow velocity with average R<sup>2</sup> equal to a 0.99. Results also demonstrated
that a strong power formula was found between hydraulic conductivity for monosized gravel and Reynolds
number with average R<sup>2</sup> equal to a 0.97. In addition, the results showed that friction factor has high values at
low Reynolds number and for Reynolds number equal to or &gt;200, friction factor decrease and it reaches an
approximately constant magnitude.
    Keywords: Forchheimer equation;hydraulic conductivity;hydraulic structures;monosized gravel;non-linear
flow;monosized gravel