Definition

1. Noun:
   • A dimensionless number representing aerodynamic resistance: The coefficient of drag is a numerical value that quantifies the aerodynamic drag or resistance of an object moving through a fluid, such as air. It is defined as the ratio of the drag force on the body to the product of the fluid's dynamic pressure and the body's reference area.

Usage

• The term is used primarily in physics, engineering, and automotive design to describe and compare the aerodynamic efficiency of shapes.
• It is a key parameter in calculating the total drag force on an object.
• It is often abbreviated as Cd.
• Example:

Examples

• Noun:
  • A streamlined shape typically has a low coefficient of drag.
  • Engineers calculated the coefficient of drag for the new aircraft wing design.
  • The vehicle's high coefficient of drag meant it consumed more energy at highway speeds.

Advanced Usage

• "Cd value": A common way to refer to the specific numerical coefficient.
  • The prototype achieved a remarkable Cd value of 0.21.
• "Drag coefficient": This is a fully synonymous term and is often used interchangeably with "coefficient of drag."
  • The drag coefficient is crucial for performance simulations.

Variants and Related Words

• Drag coefficient (n): A direct synonym for coefficient of drag.
• Cd (n): The standard abbreviation.
• Aerodynamic coefficient (n): A broader category of coefficients that includes the coefficient of drag.

Synonyms

• Drag coefficient: The most common direct synonym.
• Air resistance coefficient: A more descriptive synonym emphasizing resistance to air.

Related Phrases

• Coefficient of lift: A related aerodynamic coefficient that quantifies lift force.
• Reynolds number: A different dimensionless number in fluid dynamics that affects the coefficient of drag.

Noun

1. the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body