Definition

1. Noun:
   • A measure of a fluid's resistance to flow under an applied force: The coefficient of viscosity quantifies the internal friction within a fluid. It is a constant that relates the shear stress (force per unit area) applied to a fluid to the resulting rate of shear deformation (velocity gradient).

Usage

• The coefficient of viscosity is a fundamental property in fluid dynamics and rheology.
• It is used to characterize how easily a fluid pours or deforms. A high coefficient indicates a thick, slow-flowing fluid (like honey), while a low coefficient indicates a thin, fast-flowing fluid (like water).
• This term is primarily used in scientific, engineering, and technical contexts.

Examples

• Noun:
  • Engineers must know the coefficient of viscosity of the lubricant to ensure proper machine function.
  • The experiment aimed to determine how temperature affects the coefficient of viscosity of the polymer solution.
  • A higher coefficient of viscosity means the fluid offers more resistance to flow.

Advanced Usage

• Dynamic viscosity: This is another name for the coefficient of viscosity. It is often symbolized by the Greek letter eta (η) or mu (μ). Its SI unit is the pascal-second (Pa·s).
• In equations: The coefficient appears in Newton's law of viscosity: τ = η (du/dy), where τ is shear stress and (du/dy) is the velocity gradient.
• Kinematic viscosity: This is a related but distinct property, calculated by dividing the dynamic viscosity (coefficient of viscosity) by the fluid's density.

Variants and Related Words

• Dynamic viscosity (n): A direct synonym for coefficient of viscosity.
• Absolute viscosity (n): Another common synonym.
• Viscosity (n): A more general term for the property of being viscous. The coefficient of viscosity is the specific quantitative measure of this property.
• Newtonian fluid (n): A fluid for which the coefficient of viscosity is constant at a given temperature and pressure.

Synonyms

• Dynamic viscosity
• Absolute viscosity

Related Phrases

• Shear viscosity: Often used interchangeably with dynamic viscosity, emphasizing resistance to shear flow.
• Viscosity coefficient: A less formal but understandable variant of the term.

Noun

1. a measure of the resistance to flow of a fluid under an applied force