What is the effect of fittings and elbows on pressure loss?

• A. Each abrupt change in direction or cross-section causes turbulence and energy loss, increasing overall friction loss.
• B. Elbows and fittings reduce friction loss.
• C. They have no effect on pressure loss.
• D. They decrease turbulence.

Answer: (A)

Fittings and elbows introduce local losses by causing abrupt changes in the flow, which creates turbulence and dissipates energy, increasing the overall pressure loss. When the fluid hits a bend, a tee, or a contraction/expansion, part of its kinetic energy is lost to turbulence and eddies rather than being carried downstream as smooth flow. This is captured in the minor-loss concept, where each fitting adds a loss coefficient (K) and the head loss from that fitting is h_minor = K · v^2/(2g). The total pressure drop is the sum of the straight-pipe friction loss and these minor losses, so more fittings or sharper bends raise the total pressure loss. They do not reduce friction or eliminate turbulence; in fact, they add to it.