In most practical pipes for everyday use, the flow is primarily turbulent. The kinetic energy would just be 1/2 m*v^2, where m is the mass of a section of fluid in the pipe and v is the velocity of that fluid where you picked it.
You could solve backwards for the velocity if you knew the head loss and friction factor in the pipe (can get off a Moody chart using pipe surface roughness and the turbulence of the flow). http://en.wikipedia.org/wiki/Darcy_friction_factor
Turbulent kinetic energy is particularly useful when looking at CFD turbulence models. For example, the very standard k-ε model uses turbulent kinetic energy as one of the "transported" variables representing the turbulent properties.
We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling We Value Civility
• Positive and compassionate attitudes
• Patience while debating We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving