Question

For Darcy’s law to be valid, the Reynolds number should be ________

(a) greater than one

(b) less than one

(c) equal to one

(d) greater than five

This question was addressed to me by my school principal while I was bunking the class.

Origin of the question is Permeability in portion Permeability of Geotechnical Engineering I

Answer 1

Correct option is (b) less than one

The explanation is: The Darcy’s law is valid if flow through soils is laminar. The flow will be laminar only if the Reynolds number is less than one.