Terminal Velocity using Stoke’s Law Calculator

Terminal Velocity Calculator (Stoke’s Law)

Calculate the terminal velocity of a spherical particle in a viscous fluid using:
\[ v_t = \frac{2\,r^2\,(\rho_p – \rho_f)\,g}{9\,\mu} \] where:
– \(r\) is the particle radius (m), – \(\rho_p\) is the particle density (kg/m³), – \(\rho_f\) is the fluid density (kg/m³), – \(g\) is the acceleration due to gravity (m/s²), and – \(\mu\) is the dynamic viscosity (Pa·s).

* Enter all values in SI units.

Step 1: Enter Parameters

Example: 0.001 m (1 mm)

Example: 2500 kg/m³

Example: 1000 kg/m³

Example: 9.81 m/s²

Example: 0.001 Pa·s (for water)

Formula: \( v_t = \frac{2\,r^2\,(\rho_p – \rho_f)\,g}{9\,\mu} \)


Practical Example:
For a particle with radius 0.001 m, density 2500 kg/m³ in a fluid with density 1000 kg/m³ and viscosity 0.001 Pa·s under 9.81 m/s²:
\[ v_t = \frac{2 \times (0.001)^2 \times (2500 – 1000) \times 9.81}{9 \times 0.001} \approx 0.324\, \text{m/s} \]