A Drag Per Unit Span Calculator is a useful tool for aerodynamic and fluid dynamics calculations. It helps determine the drag force experienced per unit length of an airfoil, wing, or other streamlined body moving through a fluid. This calculation is crucial in aerodynamics, aircraft design, and fluid mechanics to optimize performance, efficiency, and energy consumption.
By inputting key variables such as fluid density, flow velocity, chord length, and drag coefficient, users can quickly compute the drag force acting along the span of a wing or similar structure. This information assists engineers and researchers in designing more aerodynamically efficient components.
Formula of Drag Per Unit Span Calculator
The formula for calculating drag per unit span is:
Drag per Unit Span = 0.5 × ρ × V² × c × Cd
Where:
- Drag per Unit Span: Measured in Newtons per meter (N/m)
- ρ (rho): Fluid density in kilograms per cubic meter (kg/m³)
- V: Flow velocity in meters per second (m/s)
- c: Chord length in meters (m)
- Cd: Sectional drag coefficient (dimensionless)
This equation helps engineers determine how much aerodynamic drag acts along a given section of a wing or similar body.
Precomputed Table for Common Values
| Fluid Density (ρ) kg/m³ | Flow Velocity (V) m/s | Chord Length (c) m | Drag Coefficient (Cd) | Drag per Unit Span (N/m) |
|---|---|---|---|---|
| 1.225 (Air) | 50 | 1.5 | 0.02 | 45.94 |
| 1.225 (Air) | 100 | 2.0 | 0.03 | 367.5 |
| 1.225 (Air) | 150 | 1.2 | 0.025 | 412.5 |
| 998 (Water) | 2 | 0.5 | 0.1 | 49.9 |
| 998 (Water) | 3 | 0.8 | 0.08 | 95.8 |
This table provides estimated values based on common parameters used in aerodynamic and fluid dynamic calculations.
Example of Drag Per Unit Span Calculator
Problem: Suppose an aircraft wing operates in air with a fluid density of 1.225 kg/m³. The airflow velocity is 120 m/s, the chord length of the wing is 2 meters, and the sectional drag coefficient is 0.025. What is the drag per unit span?
Solution: Using the formula:
Drag per Unit Span = 0.5 × (1.225) × (120)² × (2) × (0.025)
Drag per Unit Span = 0.5 × 1.225 × 14400 × 2 × 0.025 = 441 N/m
Thus, the drag per unit span for the given parameters is 441 Newtons per meter.
Most Common FAQs
Drag per unit span helps engineers optimize wing design, reducing aerodynamic resistance and improving aircraft fuel efficiency and performance.
Key factors include fluid density, velocity, wing chord length, and the drag coefficient, which depends on the shape and surface roughness of the object.
Yes, the formula is applicable to both air and water-based calculations, but fluid properties such as density and viscosity must be adjusted accordingly.