RRB JE Mechanical Question Paper 2014 (Set-1) with Answer Key

The important dimensionless numbers in fluid mechanics are
1. Reynold’s number
2. Froude’s number
3. Weber’s number
4. Euler’s number
5. Mach’s number or Cauchy’s number

Reynold’s number: It is the ratio of inertia force to the viscous force.

Froude’s number: It is the ratio of inertia force to the gravity force.

Weber’s number: It is the ratio of inertia force to the surface tension force.

Euler’s number: It is the ratio of inertia force to the pressure force.

Mach’s number or Cauchy’s number: It is the ratio of inertia force to the elastic force.