Dynamic head in hydraulic terminology refers to which of the following?

• A. Velocity head, equal to v^2/(2g)
• B. Pressure head
• C. Elevation head
• D. Temperature head

Answer: (A)

Dynamic head is the kinetic energy portion of the fluid’s energy, captured as the velocity head v^2/(2g). In Bernoulli’s framework, total head is the sum of pressure head (p/ρg), elevation head (z), and velocity head, plus any head losses. The velocity head represents how much head is tied up in the fluid’s motion, so when the fluid moves faster, dynamic head increases; if the fluid stops, dynamic head goes to zero and only pressure and elevation heads remain. The other terms correspond to different forms of energy: pressure head is due to pressure, elevation head to height, and temperature head isn’t part of standard hydraulic head calculations. Thus the dynamic or velocity head correctly matches the option v^2/(2g).