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To begin with the study, the idea is to prove that a constant diameter manifold would fail to deliver an evenly distrubuted flow along the ports. Therefore we should calculate a manifold with a constant diameter for the design flow and the desired velocity which should be higher than 0.15 m/s (minimum scour velocity). To calculate the manifold diameter we use the following equation and round diameter to a commercial drill size:

{latex}
$$
D_{SedManifold}  = \sqrt {{{4*QSedManifold} \over {V_{Scour} *\pi }}}
$$
{latex}

With the rounded Diameter, we calculated the real velocity inside the manifold using the following equation:

{latex}
$$
V_{SedManifoldMax}  = {{4*Q_{SedManifold} } \over {D_{SedManifold} ^2 *\pi }}
$$
{latex}

Now by changing the distance between ports (

{latex}$$
B_{SedManifoldOrifice}
$$ {latex}

) and we can calculate the amount of ports (

{latex}$$
N_{SedManifoldOrifice}
$$ {latex}

) needed, different ports' diameters (

{latex}$$
D_{SedManifoldOrifice}
$$ {latex}

) and also energy dissipation rates (

{latex}$$
\varepsilon _{\max }
$$ {latex}

) through those ports, by using the following equations:

{latex}
$$
N_{SedManifoldOrifice}  = floor\left( {{{L_{SedManifold} } \over {B_{SedManifoldOrifice} }}} \right)
$$
{latex}

Number of ports we can calculate the flow per port

{latex}
$$
Q_{SedManifoldOrifice}  = {{Q_{SedManifold} } \over {N_{SedManifoldOrifice} }}
$$
{latex}

Once we calculated the flow we can calculate the port's area and diameter

{latex}
$$
A_{SedManifoldOrifice}  = {{Q_{SedManifoldOrifice} } \over {Pi_{VenacontractaOrifice} *V_{SedManifoldMax} }}
$$
{

{latex}
$$
D_{SedManifoldOrifice}  = {{2*\sqrt {A_{SedManifoldOrifice} } } \over {\sqrt \pi  }}
$$
{latex}

Finally the energy dissipation rate should be checked to ensure that the flocs will not break while entering the Sedimentation Tank.

These two equations are equivalents. The first equation was derived from Monroe and the second one was provided by him also from external bibliography.

{latex}
$$
\varepsilon _{\max }  = {{\left( {0.34*V_{Jet} } \right)^3 } \over {D_{Jet} }}
$$
{

{latex}
$$
\varepsilon _{\max }  = {1 \over {20*D_{SedManifoldOrifice} }}\left( {V_{SedManifoldMax} } \right)^3
$$
{latex}

The results of those calculation proposed a 6" PVC pipe with 1" ports spaced 5 cm center to center (total 57 ports). Drilling Process Images

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