Difference between revisions of "Flow through an orifice"

Latest revision as of 19:57, 17 March 2019

Orifices are simply holes which restrict the flow of water. They may be used at the bottom end of an LID practice to add some flow control:

$Q=B\times C_{d}\times A_{o}{\sqrt {2\cdot g\cdot h}}$

Where:

B is the clogging factor (between 0.5 (for matured installation) and 1 (for a new perfectly performing orifice)),
C_d is the coefficient of discharge (usually 0.61 for a plate, or 0.8 for a pipe),
A_o is the area of the orifice (m²),
g is acceleration due to gravity = 9.81 m/s², and
h is the head of water over the centre of the orifice (m).

@@ Line 1: / Line 1: @@
-Orifices are simply holes which restrict the flow of water. They may be used at the bottom end of an LID practice to add some [[flow control]].
+Orifices are simply holes which restrict the flow of water. They may be used at the bottom end of an LID practice to add some [[flow control]]:
 <math>Q= B\times C_{d}\times A_{o}\sqrt{2\cdot g\cdot h}</math>
 {{Plainlist|1=Where:
-*''L'' is the length of perforated pipe (m)
+*''B'' is the clogging factor (between 0.5 (for matured installation) and 1 (for a new perfectly performing orifice)),
-*''B'' is the clogging factor (between 0.5 (for matured installation) and 1 (for a new perfectly performing BMP)),
 *''C<sub>d</sub>'' is the coefficient of discharge (usually 0.61 for a plate, or 0.8 for a pipe),
-*''A<sub>o</sub>'' is the area of the orifice (m<sup>2</sup>/m),
+*''A<sub>o</sub>'' is the area of the orifice (m<sup>2</sup>),
 *''g'' is acceleration due to gravity = 9.81 m/s<sup>2</sup>, and
-*''h'' is the head of water over the centre of the orifice.
+*''h'' is the head of water over the centre of the orifice (m).
 }}