FLUID MECHANICS MCQ SET 9
Q1. In a turbulent boundary layer, the velocity profile is:
A) Linear
B) Parabolic
C) Logarithmic
D) Constant
Answer: C) Logarithmic
Explanation: Turbulent flow near walls follows a logarithmic velocity distribution.
Q2. Separation of boundary layer occurs when:
A) Pressure decreases in flow direction
B) Pressure increases in flow direction
C) Velocity is maximum
D) Flow becomes laminar
Answer: B) Pressure increases in flow direction
Explanation: An adverse pressure gradient (increasing pressure) causes flow reversal and separation.
Q3. Stream function is applicable for:
A) Rotational flow
B) Irrotational flow
C) Two-dimensional incompressible flow
D) One-dimensional flow
Answer: C) Two-dimensional incompressible flow
Explanation: The stream function simplifies analysis of 2D incompressible flow patterns.
Q4. The potential function exists only for:
A) Rotational flow
B) Irrotational flow
C) Compressible flow
D) Turbulent flow
Answer: B) Irrotational flow
Explanation: A velocity potential can be defined only when the flow has zero vorticity (irrotational).
Q5. The flow through a nozzle is primarily used to:
A) Decrease velocity
B) Increase velocity
C) Increase pressure
D) Reduce discharge
Answer: B) Increase velocity
Explanation: Nozzles convert pressure energy into kinetic energy, accelerating the fluid stream.
Q6. The vena contracta is the point:
A) Before the orifice
B) Where jet area is maximum
C) Where jet area is minimum
D) Where pressure is maximum
Answer: C) Where jet area is minimum
Explanation: The fluid stream contracts just after the orifice, forming the smallest cross-section โ vena contracta.
Q7. The flow in which the velocity is same at every point at any given instant is:
A) Steady flow
B) Uniform flow
C) Laminar flow
D) Compressible flow
Answer: B) Uniform flow
Explanation: In uniform flow, velocity magnitude and direction are constant throughout the section at a given instant.
Q8. The flow in which velocity at a point does not change with time is:
A) Steady flow
B) Unsteady flow
C) Uniform flow
D) Laminar flow
Answer: A) Steady flow
Explanation: In steady flow, velocity at any fixed point remains constant with time.
Q9. A streamline is defined as a line:
A) Parallel to the direction of flow
B) Tangent to the velocity vector at every point
C) Perpendicular to velocity
D) Randomly oriented
Answer: B) Tangent to the velocity vector at every point
Explanation: Streamlines show instantaneous flow direction; tangent at any point gives fluid velocity.
Q10. The ratio of actual discharge to theoretical discharge in a Venturi meter is known as:
A) Coefficient of velocity
B) Coefficient of contraction
C) Coefficient of discharge
D) Flow ratio
Answer: C) Coefficient of discharge
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