# Water Flow Rate Through an Orifice

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## Water Flow Rate Through an Orifice formula

 $$\large{ Q_w = 0.0865 \; C_d \left( \frac{d_o}{4.654 } \right)^2 \; \sqrt { \frac{ p_1 \;-\; p_2 }{ SG } } }$$

### Where:

$$\large{ Q_w }$$ = water flow rate

$$\large{ d_o }$$ = diameter of orifice

$$\large{ C_d }$$ = discharge coefficient

$$\large{ p_1 }$$ = primary pressure

$$\large{ p_2 }$$ = secondary pressure

$$\large{ SG }$$ = specific gravity of water