Final answer:
The three turbulence criteria involve the Reynolds number to determine the flow regime: laminar (Re < 2000), transitional (2000 < Re < 4000), and turbulent (Re > 4000). Turbulent flow, especially in aviation, can cause a range of passenger reactions from mild concern to anxiety.
Step-by-step explanation:
The three turbulence criteria are related to the concept of Reynolds number, which is used to predict the flow regime of a fluid. The Reynolds number (Re) is a dimensionless value that compares the inertial forces to the viscous forces within a fluid flow and is calculated by multiplying the fluid density ρ, the velocity v, and the characteristic length L, and then dividing by the fluid's dynamic viscosity μ (Re = ρvL/μ).
- Reynolds number below 2000: This typically indicates laminar flow, where fluid particles move in smooth, orderly layers with little disruption between them.
- Reynolds number between 2000 and 4000: This range is the transition zone where the flow can alternate between laminar and turbulent; this is often an unstable and unpredictable regime.
- Reynolds number above 4000: This suggests turbulent flow, characterized by chaotic fluid motion, eddies, and vortices. Large objects moving through a fluid, such as airplanes and sailboats, often generate a turbulent wake.
Passenger reactions to turbulence can range from mild concern to anxiety, especially when the sensation of turbulence is unexpected or severe. These reactions are often a psychological response to the sudden and erratic nature of turbulent air encountered during flight.