Pipe flowing compressible fluid

[Luiz]

For pipe design flowing incompressible fluid, I use:

Darcy equation hf = f*(LV^2)/(2gD) and

Colebrook equation f = 0.25*[-log(0.27*k/D + 2.51/(Re*f^0.5))]^-2

where:
hf = friction loss
f = friction factor
L = length
V = velocity
g = gravity
D = diameter
k = equivalent roughness
Re = Reynolds number

I would like to know: how to procedure with compressible fluid?
Can anyone here help me?

Thanks.
Luiz