Blowing Force Calculator

Understanding Blowing Force

Blowing force is the mechanical force exerted when air in motion comes into contact with a surface. This force is fundamental in many engineering applications, from wind load calculations on buildings to the design of ventilation systems.

Formula

The blowing force is calculated using the following equation:

$$F = \rho \times A \times v^2$$

Where:

• ρ (rho) is the density of air in kg/m³
• A is the contact area in m²
• v is the velocity of the air in m/s

Example Calculation

Given:

• Density of Air = 1.18 kg/m³
• Contact Area = 4 m²
• Velocity of Air = 8 m/s

Calculation:

1. Square the velocity: 8² = 64 m²/s²
2. Multiply all values: 1.18 × 4 × 64 = 302.08 N

The blowing force is 302.08 Newtons.

Factors Affecting Blowing Force

Air Density: Air density decreases with altitude and increases with lower temperatures. Standard sea level density is 1.225 kg/m³.

Contact Area: The larger the surface area exposed to the airflow, the greater the total force exerted.

Velocity: Force increases with the square of velocity, meaning doubling the air speed quadruples the force.

Practical Applications

• Structural Engineering: Calculating wind loads on buildings and structures
• HVAC Design: Determining airflow forces in ductwork and ventilation systems
• Aerospace: Analyzing aerodynamic forces on aircraft surfaces
• Automotive: Evaluating drag forces and wind resistance on vehicles