Question

What is the property of an ideal or perfect fluid?

(a) Compressible and zero viscosity

(b) Compressible and zero density

(c) Incompressible and zero viscosity

(d) Incompressible and zero density

This question was addressed to me at a job interview.

The origin of the question is Classification of Fluids topic in division Fluid Flow and Mixing of Bioprocess Engineering

Answer 1

Right choice is (c) Incompressible and zero viscosity

For explanation: Viscosity is the property of fluids responsible for internal friction during flow. An ideal or perfect fluid is a hypothetical liquid or gas which is incompressible and has zero viscosity. The term inviscid applies to fluids with zero viscosity.