#### Calculating Length and Equivalent Length in a Pipe: Screencast

Describes how to calculate an equivalent length for minor losses.

We suggest you list the important points in this screencast as a way to increase retention.

##### Important Equations:

$Re = \frac{\rho \, UD}{\mu} = \frac{UD}{\nu}$

where $$Re$$ = Reynold’s number, $$\rho$$ = fluid density, $$U$$ = freestream velocity, $$D$$ = pipe diameter, $$\mu$$ = fluid dynamic viscosity, and $$\nu$$ = fluid kinematic viscosity.

$\frac{P_1}{\gamma} + \frac{V_1 ^2}{2g} + z_1 = \frac{P_2}{\gamma} + \frac{V_2 ^2}{2g} + z_2 + h_L$

where $$P_1$$ and $$P_2$$ are the pressures at points 1 and 2, $$\gamma$$ = specific weight of fluid, $$V_1$$ and $$V_2$$ are the velocities at points 1 and 2, $$g$$ = gravitational constant (9.81 m/s2), $$z_1$$ and $$z_2$$ are the relative heights at points 1 and 2, and $$h_L$$ = head loss.

$$h_L$$ consists of 2 components: major head loss and minor head loss.

$h_{L,major} = f \frac{L}{D} \frac{V^2}{2g}$

where $$f$$ = friction factor, and $$L$$ = length of pipe.

$h_{L,minor} = \frac{K_L V^2}{2g} = \frac{f \left( \frac{L_{eq}}{D} \right) V^2}{2g}$

$L_{eq} = \frac{K_L D}{f}$

where $$K_L$$ = loss coefficient and $$L_{eq}$$ = equivalent length.