At a sudden contraction in a pipe the diameter changes from D1 to D2. The pressure drop, Δp, which develops across the contraction is a function of D1 and D2 as well as the velocity, V, in the larger pipe, and the fluid density, rho, and viscosity, μ. Use D1, V, and μ as repeating variables to determine a suitable set of dimensionless parameters. Find how many pi terms are required to describe this problem. Why would it be incorrect to include the velocity in the smaller pipe as an additional variable?

Refer below.

Explanation:

Refer to the picture for brief explanation.

t.                 w               e                 n                   t                 y                 c             h               a           r           a               c                 t             e             r             s        

potential energy is directly proportional to height.

more height = more potential energy.

greatest increase in height = greatest increase in potential energy

where are the points with the greatest increase in height ?

has to be c-e or d-e .