Answer: Flow smoothly in parallel without mixing.
- A Flow smoothly in parallel without mixing
- B Mix chaotically as generally observed
- C Flow turbulently in typical laboratory settings
- D Create eddies and vortices under usual circumstances
Correct answer: A. Flow smoothly in parallel without mixing
Explanation: In laminar flow, fluid flows in smooth, parallel layers. This occurs at low velocities (low Reynolds number). At high velocities, flow becomes turbulent.
Since the same volume of fluid must pass every cross-section per second (continuity), the fluid speeds up where the pipe narrows; Bernoulli's equation then says this faster-moving fluid has lower pressure - the principle behind a venturi meter and an aircraft wing's lift.
Concept context
Pressure, buoyancy, Bernoulli equation, viscosity, and surface tension.