A classic fluid-mechanics setup to visualize flow regimes in a pipe and determine the critical Reynolds number. A dye is injected into a transparent test section while water flow is varied. A smooth, straight dye filament indicates laminar flow; wavy/broken mixing indicates turbulent flow. Flow rate is measured to compute Reynolds number and identify the laminar–transition–turbulent boundaries.

Parts Used:

1. Water Reservoir (overhead/bench tank)
2. Centrifugal Pump (constant head) or gravity feed
3. Flow Straightener/Settling Chamber (honeycomb/screen)
4. Transparent Test Section (Pipe) with inner diameter D (e.g., acrylic)
5. Dye Injection System: dye tank, needle/nozzle, fine control valve
6. Flow Control Valve (downstream preferred to keep test section pressure stable)
7. Measuring Tank / Volumetric Flask + Stopwatch or Rotameter (to find flow rate Q)
8. Thermometer (to estimate fluid properties at temperature)
9. Drain & Return Lines (closed-loop recommended)
10. Optional: Differential manometer/tappings for head-loss studies, scale/ruler along test section