The performance of a turbo-machine like pumps, water turbines, fans or blowers for incompressible flow can be expressed as a function of: 

(i) Density of the fluid, ρ, 

(ii) Speed of the rotor, N, 

(iii) Characteristic diameter, D, 

(iv) Discharge, Q, 

(v) Gravity head (gH), 

(vi) Power developed, P  

(vii) Viscosity, μ. 

Using dimensional analysis, obtain dimensionless groups and explain their significance.