Dynamic Viscosity Given Drag Force As Per Stokes Law Calculator

Stokes Law Formula:

\[ \mu = \frac{F_D}{\pi \times 3 \times V_s \times D} \]

Dynamic Viscosity (μ):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Stokes Law?

Stokes Law describes the force of viscosity on a sphere moving through a viscous fluid at low Reynolds numbers. It provides a relationship between drag force and fluid viscosity for spherical particles.

2. How Does the Calculator Work?

The calculator uses the Stokes Law formula:

\[ \mu = \frac{F_D}{\pi \times 3 \times V_s \times D} \]

Where:

\( \mu \) — Dynamic viscosity (Pa·s)
\( F_D \) — Drag force (N)
\( \pi \) — Mathematical constant pi (≈3.1416)
\( V_s \) — Settling velocity (m/s)
\( D \) — Diameter of the sphere (m)

Explanation: The formula calculates the dynamic viscosity of a fluid based on the drag force experienced by a spherical particle moving through it at a known velocity.

3. Importance of Dynamic Viscosity Calculation

Details: Dynamic viscosity is a crucial property in fluid mechanics that determines a fluid's resistance to flow. It's essential for designing fluid systems, predicting flow behavior, and understanding transport phenomena in various engineering applications.

4. Using the Calculator

Tips: Enter drag force in Newtons, settling velocity in m/s, and diameter in meters. All values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What are the limitations of Stokes Law?
A: Stokes Law is valid only for small spherical particles at low Reynolds numbers (Re < 0.1) in laminar flow conditions.

Q2: What is the typical range of dynamic viscosity values?
A: Dynamic viscosity ranges from about 0.00089 Pa·s for air to 1.002 Pa·s for water at 20°C, and can be much higher for oils and other viscous fluids.

Q3: How does temperature affect viscosity?
A: For liquids, viscosity generally decreases with increasing temperature, while for gases, viscosity increases with temperature.

Q4: What units are used for dynamic viscosity?
A: The SI unit is Pascal-second (Pa·s), but centipoise (cP) is also commonly used (1 Pa·s = 1000 cP).

Q5: When is this calculation most applicable?
A: This calculation is most applicable for small spherical particles settling in viscous fluids, such as in sedimentation processes, particle size analysis, and microfluidic applications.