Mechanical Aptitude Fluid Dynamics Principles Flashcards
7 cards from real MECHANICAL APTITUDE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Mechanical Aptitude Fluid Dynamics Principles flashcards as text
Two pipes of equal length carry the same fluid at the same pressure difference. Pipe A has a diameter of 1 inch and Pipe B has a diameter of 2 inches. Which carries more flow?
Answer: Pipe B carries more flow
By the Hagen-Poiseuille equation, flow rate is proportional to the fourth power of radius, so doubling diameter increases flow by a factor of 16.
What does the Reynolds number indicate about fluid flow?
Answer: Whether flow is laminar or turbulent
The Reynolds number predicts flow regime: below ~2,300 is laminar, above ~4,000 is fully turbulent, and in between is transitional.
A ship floats because it displaces a volume of water whose weight equals the ship's total weight. This is a direct application of:
Answer: Archimedes' principle
Archimedes' principle states that a floating object displaces fluid equal in weight to the object's own weight.
In a fluid system, a manometer is used to measure:
Answer: Pressure differences
A manometer measures pressure by comparing fluid column heights, giving direct readings of pressure or pressure differences.
When selecting a centrifugal pump for a system, what does the 'head' rating refer to?
Answer: The energy added to the fluid per unit weight, expressed as a height
Pump head is the energy per unit weight of fluid, equivalent to the height the pump could raise the fluid against gravity.
A fluid is described as 'incompressible.' What does this mean in practical terms for most hydraulic calculations?
Answer: The fluid's density remains essentially constant under pressure changes
Incompressible fluids like water maintain constant density regardless of pressure changes, which greatly simplifies hydraulic calculations.
What happens to the pressure at the bottom of a tank if you double the depth of water but keep the tank's base area the same?
Answer: Pressure at the bottom doubles
Hydrostatic pressure P = ρgh, so doubling depth (h) directly doubles the pressure at the bottom.