alleryReynolds number Re is dimensionless and given by Re = ρ v d / η, where d is a characteristic length. For Re ≪ 1, the flow is:
ATurbulent and chaotic
BInviscid (no viscosity)
CSupersonic in regime
DLaminar and smooth
Answer & Solution
Correct answer: D. Laminar and smooth
1. Re compares inertial to viscous forces.
2. Small Re means viscous effects dominate — flow is smooth and laminar.
3. Above roughly Re ~ 2000–3000, flow becomes turbulent.
_Source: syllabus Physics Ch 9 §9.7 Reynolds Number_
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