Question

In Fluid dynamics, Reynold’s number is a dimensionless number. True or False?

(a) False

(b) True

I had been asked this question during an online interview.

This intriguing question comes from Unit Systems topic in portion Introduction & Unit Systems of Food Processing Unit Operations

Answer 1

Right choice is (b) True

For explanation I would say: In fluid dynamics, inertial forces are very important and the ratio of these inertial forces to viscous, pressure, gravity, surface tension and compressibility forces lead to formation of fundamental dimensionless groups. Reynold’s number is the ratio of inertial force to viscous force and is thus, dimensionless.