Fluid Kinematics MCQ with answer and solution

Concept

Mathematical condition for steady-state fluid flow

Formula

∂ V / ∂ t = 0, ∂ p / ∂ t = 0

Step-by-step solution

1. Flow classification evaluates whether fluid properties change with time or with spatial coordinates. 2. Flow is uniform when velocity and depth are constant along the flow path at any instant (∂ V / ∂ s = 0). 3. Flow is steady-state when fluid properties (velocity, pressure, density) at any fixed spatial point do not change with time (∂ / ∂ t = 0). 4. Thus, option C accurately defines steady flow. Answer: C

Explanation

A fluid flow is classified as steady-state when fluid properties such as velocity, pressure, density, and temperature at any fixed spatial point do not change with respect to time. If fluid parameters at a point vary over time, the flow is unsteady.

Why the other options are wrong

A) Identical velocity at all points describes uniform flow, not steady flow. B) Incompressible flow refers to constant fluid density, which can be steady or unsteady. D) A straight flow path describes rectilinear flow.

Shortcut

Steady flow = No change with time at a fixed point (∂/∂ t = 0).

Common mistake

Confusing steady flow (constant with time) with uniform flow (constant in space).