The highly disordered fluid motion characterized by clear eddies is called transitional flow. Select one:
True
False
The correct answer and explanation is:
Correct Answer: ❌ False
Explanation:
The statement “The highly disordered fluid motion characterized by clear eddies is called transitional flow” is false. The correct term for highly disordered fluid motion with clear eddies is turbulent flow, not transitional flow.
Understanding Fluid Flow Types:
Fluid flow can be categorized into laminar, transitional, and turbulent based on the Reynolds number (a dimensionless number that predicts flow regimes):
1. Laminar Flow:
- Fluid moves in smooth, parallel layers (streamlines).
- No mixing between layers.
- Occurs at low Reynolds numbers (Re < ~2,000).
2. Transitional Flow:
- Intermediate state between laminar and turbulent flow.
- Occurs at Reynolds numbers between ~2,000 and 4,000.
- Flow shows some instabilities, but not yet fully chaotic.
- Eddies may begin to form, but they are not dominant or sustained.
3. Turbulent Flow:
- Highly chaotic and irregular.
- Characterized by clear eddies, swirls, and vortices.
- Happens at high Reynolds numbers (Re > ~4,000).
- Significant mixing and momentum exchange.
Key Characteristics of Turbulent Flow:
- Highly disordered motion.
- Well-defined and persistent eddies.
- Rapid fluctuations in velocity and pressure.
- Common in high-speed flows like in rivers, blood vessels, or airplane wings at cruise speed.
Summary:
While transitional flow shows early signs of instability, it is not yet fully disordered and does not feature well-defined eddies. These are the hallmarks of turbulent flow, making the statement false.