A Reynolds number condenses density, speed, length, and viscosity into one dimensionless ratio that classifies flow as laminar or turbulent against a teaching threshold. The training ratio Re = 6 falls below threshold 10, classifying the flow as laminar exactly for the stated toy parameter ledger; real channels have geometry tolerances, viscosity and temperature variation, wall roughness, and threshold-region ambiguity.
A simplified Reynolds number is a dimensionless transport ratio. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Reynolds number is dimensionless
Density, speed, length, and viscosity reduce to the dimensionless training ratio 6.
Re=μρvL=6
A threshold makes the classification explicit
The threshold is 10, and 6 is below it. The threshold is a teaching rule, not a universal boundary.