Drag Force Formula:
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Definition: Drag force is the resistance force caused by the motion of a body through a fluid (liquid or gas).
Purpose: This calculator helps engineers, physicists, and students determine the aerodynamic or hydrodynamic drag on objects moving through fluids.
The calculator uses the formula:
Where:
Explanation: The formula shows drag force increases with the square of velocity, directly with fluid density, drag coefficient, and reference area.
Details: Accurate drag calculations are essential for designing vehicles, aircraft, ships, and understanding fluid flow around structures.
Tips: Enter fluid density (1.225 kg/m³ for air at sea level), velocity, drag coefficient (0.47 for sphere), and reference area. All values must be > 0 (velocity can be 0).
Q1: What is a typical drag coefficient value?
A: It varies by shape: ~0.47 for sphere, ~1.05 for cube, ~0.04 for streamlined airfoil.
Q2: How do I determine reference area?
A: For most applications, use frontal area (projected area facing flow direction).
Q3: What fluid density should I use?
A: 1.225 kg/m³ for air at 15°C sea level; 1000 kg/m³ for water; check tables for other fluids.
Q4: Does this formula work for all velocities?
A: It works well for subsonic speeds; different considerations apply near or above speed of sound.
Q5: How does drag force affect vehicle design?
A: Higher drag means more energy needed to move, affecting fuel efficiency and maximum speed.