1. What is Buoyancy Calculation?

The buoyancy calculation determines the upward force exerted by a fluid on an immersed object. For underground tanks, this helps determine if the tank will float or remain submerged when empty.

2. How Does the Calculator Work?

The calculator uses the buoyancy formula:

Where:

• \( F_b \) — Buoyancy force (N)
• \( \rho \) — Fluid density (kg/m³)
• \( V \) — Displaced volume (m³)
• \( g \) — Gravitational acceleration (9.81 m/s²)
• \( \text{weight} \) — Weight of the tank (N)

Explanation: The equation calculates the net upward force on the tank by subtracting its weight from the buoyant force of the displaced fluid.

3. Importance of Buoyancy Calculation

Details: Accurate buoyancy calculation is crucial for designing underground tanks to prevent floating when empty, which could damage piping and structural connections.

4. Using the Calculator

Tips: Enter fluid density in kg/m³, displaced volume in m³, and tank weight in N. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical fluid density for groundwater?
A: Fresh water density is typically 1000 kg/m³, while brackish water may be 1020-1050 kg/m³.

Q2: How do I determine the displaced volume?
A: For completely submerged tanks, displaced volume equals the tank's total volume. For partially submerged, use the submerged portion's volume.

Q3: What if the buoyancy force is positive?
A: A positive result means the tank may float. Additional anchoring or ballast weight would be needed.

Q4: Should safety factors be applied?
A: Yes, typically a safety factor of 1.2-1.5 is applied to account for water table fluctuations.

Q5: How does soil type affect buoyancy?
A: While the calculation focuses on fluid buoyancy, soil type affects groundwater levels and thus the actual buoyant force experienced.