Stokes' Law Calculator

Calculate the drag force on a sphere moving through a viscous fluid.

Input Parameters

Dynamic Viscosity (μ) (Pa·s)

Sphere Radius (r) (m)

Velocity (v) (m/s)

Calculation Results

Enter parameters to calculate

Quick Reference

μDynamic viscosity

rRadius of the sphere

vVelocity of the sphere

FViscous drag force

Overview

Stokes' Law describes the drag force exerted on spherical objects with very small Reynolds numbers in a viscous fluid.

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Pro Tips

The formula is F = 6 * π * μ * r * v.
μ is the dynamic viscosity of the fluid (e.g., water ≈ 0.001 Pa·s).
This law is key to understanding terminal velocity for small particles like fog droplets or sediment.

Fun Facts

"George Gabriel Stokes, an Irish physicist, derived this formula in 1851."
"The law only applies to 'laminar' flow, where the fluid moves in smooth layers with no turbulence."
"It explains why tiny dust particles can stay suspended in the air for a long time."

Formula: F = 6πμrv

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