Laminar Friction Coefficient

Overview

Engineering reference data for Laminar Friction Coefficient in material science and properties.

Key Formulas

Stress

$\sigma = \frac{F}{A}$

Force per unit area.

Strain

$\varepsilon = \frac{\Delta L}{L_0}$

Change in length per original length.

Hooke's Law

$\sigma = E \varepsilon$

Stress proportional to strain in elastic region.

Thermal Expansion

$\Delta L = \alpha L_0 \Delta T$

Length change due to temperature.

Variables

Flow Regime Validity

The formula for the laminar friction coefficient is applicable under specific conditions:

$\lambda = \frac{64}{Re} = \frac{64 \mu}{d_h u \rho} = \frac{64 \nu}{d_h u}$

This equation is valid only for laminar flow where the Reynolds number ($Re$) is less than 2300. For turbulent flow regimes where $Re$ exceeds 4000, the Colebrook equation is used instead to determine the friction coefficient.

Viscous Fluid Applications

Laminar flow is typically observed with viscous fluids in engineering practice. Common examples include crude oil, fuel oil, and other similar oils, where flow velocities and diameters result in low Reynolds numbers.

Moody Diagram Reference

The friction coefficient for laminar flow is depicted in the Moody diagram, a standard tool in fluid mechanics for visualizing friction factors across different flow regimes and pipe conditions.

References

• Original Source