1. What is the Drag Force in Falling Sphere Resistance Method?

The Drag Force in Falling Sphere Resistance Method is the resisting force experienced by a sphere moving through a fluid. This method is commonly used to measure fluid viscosity by observing the terminal velocity of a falling sphere.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( F_D \) — Drag Force (N)
• \( \pi \) — Archimedes' constant (≈3.1416)
• \( \mu \) — Viscosity of Fluid (Pa·s)
• \( U \) — Velocity of Sphere (m/s)
• \( d \) — Diameter of Sphere (m)

Explanation: This formula calculates the drag force on a sphere moving through a viscous fluid, derived from Stokes' law for low Reynolds number flows.

3. Importance of Drag Force Calculation

Details: Accurate drag force calculation is crucial for fluid dynamics analysis, viscosity measurement, and designing systems involving particle motion in fluids.

4. Using the Calculator

Tips: Enter viscosity in Pa·s, velocity in m/s, and diameter in m. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of validity for this formula?
A: This formula is valid for low Reynolds numbers (Re < 0.1) where Stokes' law applies.

Q2: Can this calculator be used for non-spherical objects?
A: No, this formula is specifically derived for spherical objects moving through fluids.

Q3: What fluids can this be used for?
A: This can be used for Newtonian fluids where viscosity remains constant with changing shear rate.

Q4: Are there limitations to this equation?
A: The equation assumes the sphere is far from boundaries, the flow is laminar, and the fluid is incompressible.

Q5: How accurate is this calculation?
A: The calculation is mathematically exact for the given inputs within the valid range of Stokes' law.