EIT Fluid Mechanics 2 — Questions and Answers
Question 1: The Darcy-Weisbach equation is used to calculate:
- Buoyant force
- Hydraulic pressure at a point
- Head loss due to friction in a pipe (Correct answer)
- Velocity of flow at a nozzle
Correct answer: Head loss due to friction in a pipe
The Darcy-Weisbach equation hf = f(L/D)(v²/2g) gives the head loss due to pipe friction.
Question 2: What is the Mach number of a flow with velocity 340 m/s in air where the speed of sound is 340 m/s?
- 0.5
- 1.0 (Correct answer)
- 2.0
- 0.34
Correct answer: 1.0
Mach number M = v/c = 340/340 = 1.0, representing exactly sonic flow.
Question 3: Which type of flow has fluid layers moving parallel to each other without mixing?
- Turbulent flow
- Transitional flow
- Laminar flow (Correct answer)
- Compressible flow
Correct answer: Laminar flow
Laminar flow consists of parallel layers (laminae) with no lateral mixing, occurring at low Reynolds numbers.
Question 4: A Pitot tube measures:
- Fluid viscosity
- Static pressure only
- Stagnation (total) pressure (Correct answer)
- Flow rate
Correct answer: Stagnation (total) pressure
A Pitot tube converts kinetic energy to pressure energy, measuring stagnation (total) pressure at a point.
Question 5: What is the hydraulic diameter of a square duct with side length a?
- a (Correct answer)
- 2a
- 4a
- a/2
Correct answer: a
The hydraulic diameter D_h = 4A/P = 4a²/4a = a for a square cross-section.
Question 6: In fluid statics, the center of pressure on a submerged vertical surface is located:
- At the centroid of the surface
- Above the centroid
- Below the centroid (Correct answer)
- At the free surface
Correct answer: Below the centroid
The center of pressure is always below the centroid because pressure increases with depth, shifting the resultant force downward.
EIT Fluid Mechanics 2
The Darcy-Weisbach equation is used to calculate: