Difficulty: Easy
Correct Answer: p/γ + v^2/(2g) + z = constant
Explanation:
Introduction / Context:
Bernoulli’s equation is the energy conservation statement for steady, inviscid, incompressible flow along a streamline. It relates pressure head, velocity head, and elevation head, and is ubiquitous in hydraulics and aerodynamics.
Concept / Approach:
The “familiar” head form sums three terms: pressure head p/γ (where γ = ρ * g), velocity head v^2/(2g), and elevation head z. Their sum equals a constant along a streamline in the absence of pumps, turbines, or losses. Extensions add pump/turbine heads and losses as needed.
Step-by-Step Solution:
Verification / Alternative check (if short method exists):
Dimensional analysis confirms each term has dimensions of length (head). Laboratory ventures (Venturi, Pitot) rely on this relation.
Why Other Options Are Wrong:
Option (b) is the differential Euler form; (c) mixes per-unit-mass constants with raw terms; (d) and (e) omit key terms, valid only under very restrictive conditions.
Common Pitfalls (misconceptions, mistakes):
Applying Bernoulli across devices with energy addition/removal without correction; using it across widely separated streamlines in rotational flows.
Final Answer:
p/γ + v^2/(2g) + z = constant
Discussion & Comments