Question

Which of the following is not the property of an ideal fluid?

• A. Fluid flow is irrotational
• B. Fluid flow is streamline
• C. Fluid is incompressible
• D. Fluid is viscous

Answer 1

The correct option is D Fluid is viscous

Fluids which don't have viscosity and are incompressible are termed as ideal fluids. Such fluids do not offer shear resistance.
For incompressible fluid, ${\rho }_{\text{fluid}}=\text{constant}$
Ideal fluid follows streamline flow, in which there are no abrupt fluctuations in fluid flow and flow lines are spaced parallely.

Fluids which do posses viscosity are termed as real fluids. These fluids can withstand shear stress, and shear stress varies according to varying velocity of different fluid layers.
$\therefore$Option $\left(d\right)$ is not a property of an ideal fluid.