Reynolds numbers

Noun

Reynolds number (plural Reynolds numbers)

1. A dimensionless parameter that determines the behavior of viscous flow patterns. In pipe flow a value less than roughly 2,000 (known as the critical Reynolds number) produces laminar flow, one above about 3,000 produces turbulent flow (intermediate values produce unpredictable behavior).
   • One certainly can argue that not all low-speed streaks lead to liftup, although if the local Reynolds number exceeds the transition limit, it is certain that eventual transition will occur to the hairpin vortex liftup, which ultimately leads to the breakup state.1995, William Lawrence Keith, Flow Noise Modeling, Measurement, and Control, page 45