Water Surface Tension

Reference data and engineering information about water surface tension for fluid mechanics applications.

watersurfacetension

Overview

Engineering reference data for Water Surface Tension in fluid mechanics.

Key Formulas

Reynolds Number

$Re = \frac{\rho v D}{\mu}$

Ratio of inertial to viscous forces — determines flow regime.

Bernoulli's Equation

$P + \frac{1}{2}\rho v^2 + \rho g h = \text{const}$

Conservation of energy for steady, inviscid, incompressible flow.

Continuity Equation

$A_1 v_1 = A_2 v_2$

Conservation of mass for incompressible flow.

Darcy-Weisbach

$\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}$

Pressure drop due to friction in a pipe.

Variables

Symbol	Description	Unit
$Re$	Reynolds number	—
$\rho$	Fluid density	kg/m³
$v$	Flow velocity	m/s
$D$	Characteristic dimension	m
$\mu$	Dynamic viscosity	Pa·s
$P$	Pressure	Pa
$f$	Darcy friction factor	—

Surface Tension Data Tables

The surface tension of water in contact with air decreases as temperature increases. Below are the tabulated values for both Imperial (U.S. Customary) and SI units.

Imperial Units (U.S. Customary)

14 rows

Surface tension of water in contact with air, Imperial units.
Temperature(°F)	Surface Tension (σ)(×10⁻³ lb/ft)
32	5.18
40	5.13
50	5.09
60	5.03
70	4.97
80	4.91
90	4.86
100	4.79
120	4.67
140	4.53
160	4.4
180	4.26
200	4.12
212	4.04

Source: engineeringtoolbox.com

SI Units

18 rows

Surface tension of water in contact with air, SI units.
Temperature(°C)	Surface Tension (σ)(×10⁻² N/m)
0	7.56
5	7.49
10	7.42
20	7.28
30	7.12
40	6.96
50	6.79
60	6.62
70	6.44
80	6.26
90	6.08
100	5.89
150	4.82
200	3.76
250	2.64
300	1.47
350	0.37
374.1	0

Source: engineeringtoolbox.com

Interactive Charts

Surface tension water air

Surface tension of water in contact with air, SI units.

References

Original Source

Source: engineeringtoolbox.com