What is the difference between laminar and turbulent flow?

Laminar flow is characterized by smooth, orderly fluid motion in parallel layers with no mixing between layers, occurring at low Reynolds numbers (Re < 2300 in pipes). Turbulent flow has chaotic, irregular motion with significant mixing, eddies, and fluctuations, occurring at high Reynolds numbers (Re > 4000). The transition region exists between Re 2300-4000. Turbulent flow has higher energy losses due to increased friction but provides better heat and mass transfer due to enhanced mixing.