Laminar boundary layer thickness over a flat plate under zero pressure gradient varies along the x-direction as x0.5, whereas turbulent boundary layer thickness varies as (where x = distance from leading edge)?
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Answer: B. x0.8
Explanation
Turbulent boundary layer thickness over a flat plate grows proportionally to the distance coordinate raised to the zero point eight power. This mathematical growth rate reflects the intense momentum mixing characteristic of turbulent fluid flows near solid surfaces. Empirical fluid mechanics derivations confirm that turbulent boundary layers thicken much faster than laminar boundary layers. Boundary layers develop when viscous fluids flow past solid stationary surfaces, creating distinct velocity profile regions. The transition from laminar to turbulent flow occurs when local Reynolds numbers exceed critical threshold values. Blasius solutions provide the classic theoretical proof for laminar boundary layer growth proportional to x to the zero point five power.
Exponents such as one point five do not correspond to any standard flat plate boundary layer growth correlations. Negative exponent values like x to the minus one point five would imply shrinking boundary layers downstream, which is impossible. Other incorrect mathematical variations fail to match established empirical boundary layer growth equations for flat plates.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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