How do you convert Stokes to Square millimeter per second?

Multiply the value in Stokes by the conversion factor 100.00000000000001 to obtain the result in Square millimeter per second.

Convert Stokes to Square millimeter per second (St to mm²/s)

Reference ID: EC-KINE-STMM | EngConverter Calculation Guide

Convert From (Stokes):

Result To (Square millimeter per second):

mm²/s

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In the field of fluid mechanics and process engineering, kinematic viscosity is a fundamental property that describes a fluid's resistance to flow under the influence of gravity. The conversion from Stokes (St) to Square millimeter per second (mm²/s) represents a transition between the older CGS (centimeter-gram-second) system and the modern SI-derived units. One Stokes is defined as one square centimeter per second (1 cm²/s). Since 1 centimeter equals 10 millimeters, 1 square centimeter equals 100 square millimeters, establishing the primary relationship between these units.

Engineering Applications & Technical Considerations

Kinematic viscosity is a critical parameter in several engineering domains:

Piping and Fluid Transport: Engineers use kinematic viscosity to calculate the Reynolds Number $ Re = \frac{vD}{\nu} $, which determines whether a flow is laminar or turbulent. This directly impacts pressure drop calculations and pump head requirements.
Equipment Sizing: In the design of heat exchangers and industrial mixers, viscosity dictates the boundary layer thickness and heat transfer coefficients.
Instrumentation: Many flowmeters, particularly turbine and positive displacement meters, are sensitive to viscosity changes, requiring compensation factors to maintain accuracy.

When performing conversions in a professional environment, engineers must be wary of several critical pitfalls. First, temperature dependency is paramount; kinematic viscosity varies significantly with temperature. A value reported in Stokes without a reference temperature is technically incomplete. Second, ensure the distinction between kinematic viscosity (measured in St or mm²/s) and dynamic viscosity (measured in Poise or Pa·s). To convert between them, the fluid density $ \rho $ must be known: $ u = \frac{\mu}{\rho} $. Finally, while the theoretical conversion factor is exactly 100, high-precision computational tools may utilize extended floating-point representations, such as the factor 100.00000000000001, to account for specific software-defined tolerances or legacy data alignment.

Stokes to Square millimeter per second Conversion Reference Table

Stokes (St)	Square millimeter per second (mm²/s)
0.1	10
0.5	50
1.0	100
2.0	200
5.0	500
10.0	1000
20.0	2000
50.0	5000
100.0	10000
500.0	50000
1000.0	100000

To convert a kinematic viscosity value from Stokes (St) to Square millimeter per second (mm²/s), multiply the value by the conversion factor 100.00000000000001. For a fluid with a viscosity of 10 St:

\$$ \nu_{\text{mm}^2/\text{s}} = 10 \text{ St} \times 100.00000000000001 = 1000.0000000000001 \text{ mm}^2/\text{s} \$$

This result indicates that a fluid with a viscosity of 10 Stokes flows at a rate equivalent to approximately 1000 mm²/s, which is also equivalent to 1000 centiStokes (cSt).

In industrial practice, 1 mm²/s is exactly equal to 1 centiStokes (cSt). Because 1 Stokes equals 100 centiStokes, the conversion to mm²/s follows the same magnitude. Most modern data sheets use mm²/s to comply with ISO standards, but engineers often use the terms interchangeably.

Kinematic viscosity is preferred in gravity-driven flow and pipe friction calculations because it inherently includes the density of the fluid. Since the force driving the flow (gravity or pressure head) often acts on the mass of the fluid, the ratio of internal resistance to density (kinematic viscosity) simplifies the governing equations of motion.

"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison."
"Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house."
— Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)