About Stokes’ Law Calculator (Formula)
Stokes’ Law Calculator is a tool used in fluid mechanics and particle dynamics to estimate the drag force experienced by small spherical particles (typically in the submillimeter range) as they settle through a viscous fluid, such as air or a liquid. This law is especially relevant in fields like chemistry, physics, and environmental science. The formula for calculating the drag force according to Stokes’ Law is as follows:
F = 6πηrv
Where:
- F represents the drag force experienced by the particle (measured in Newtons, N).
- π (pi) is a mathematical constant approximately equal to 3.14159.
- η (eta) is the dynamic viscosity of the fluid (measured in pascal-seconds, Pa·s, or N·s/m²).
- r is the radius of the spherical particle (measured in meters, m).
- v is the velocity of the particle as it settles through the fluid (measured in meters per second, m/s).
Stokes’ Law is applicable under specific conditions, namely when the Reynolds number (Re) is much less than 1. The Reynolds number is a dimensionless parameter that characterizes the flow regime. In the case of very small, slow-moving particles, the Reynolds number remains well below 1, and the simplified Stokes’ Law can be used.
The formula indicates that the drag force is directly proportional to the velocity of the particle and the radius of the particle and is inversely proportional to the dynamic viscosity of the fluid. Stokes’ Law is particularly useful for understanding and predicting the behavior of small particles in fluid environments, such as the settling of dust particles in air or the sedimentation of fine particles in liquids.
A Stokes’ Law Calculator simplifies the process of determining drag forces and particle settling rates, making it a valuable tool for researchers, scientists, and engineers working with small particles in fluid dynamics and particle analysis applications.