Question

The ratio of inertial forces to viscous forces is known as

• A. Coefficient of viscosity
• B. Reynolds number
• C. Fluid compressibility
• D. None of these

Answer 1

The correct option is B Reynolds number

Reynolds number is defined as the ratio of inertial forces to the viscous forces for a fluid.
$Re=\frac{\text{Inertial force}}{\text{Viscous force}}=\frac{\rho vD}{\eta }$
where $v\to$ Fluid velocity
$\eta \to$ Fluid viscosity
$D\to$ Diameter of flow conduit