Fluid Mechanics & Experimental Methods

Fluid Flow in a Smooth Pipe — Reynolds Regime Classification, Friction Factor Measurement & Moody Chart Validation

An experimental investigation of internal pipe flow across laminar and turbulent regimes: Reynolds numbers computed from measured volumetric flow rates and pipe geometry to classify flow regime, friction factors extracted from differential pressure readings under controlled conditions, and results benchmarked against both the Moody chart and the Darcy–Weisbach analytical model — with systematic uncertainty propagation from raw instrumentation readings through to final derived quantities.

Differential pressure measurement · volumetric flow rate metering · Reynolds number & friction factor analysis · Moody diagram & Darcy–Weisbach model · uncertainty propagation
Experimental Setup & Flow Regime Analysis
  • Computed Reynolds numbers from measured volumetric flow rate, pipe inner diameter, and fluid kinematic viscosity, and used the results to classify each test condition as laminar, transitional, or turbulent relative to the standard regime thresholds.
  • Controlled and varied flow rates across the full regime spectrum to capture the characteristic behaviour of each — confirming the expected dependence of regime on flow velocity rather than pressure alone.
  • Interpreted physical flow behaviour from Reynolds number magnitudes, connecting the dimensionless parameter to the relative dominance of inertial versus viscous forces within the pipe cross-section.
Friction Factor Measurement & Model Validation
  • Extracted Darcy friction factors from differential pressure measurements across a known pipe length using the Darcy–Weisbach head-loss equation, rearranging the model to isolate friction factor as the dependent variable.
  • Plotted measured friction factors against computed Reynolds numbers and overlaid results on the Moody chart, assessing agreement with the laminar theoretical line and the Colebrook–White correlation in the turbulent regime.
  • Quantified instrumentation uncertainty at source (flow meter, pressure transducer) and propagated errors through derived quantities using partial-derivative methods, producing confidence intervals on reported friction factors.
  • Identified and attributed systematic deviations between measured and theoretical values to physical contributors — minor losses, inlet effects, temperature-driven viscosity variation, and instrument resolution limits — ranked by expected significance.