Question

For an ideal fluid flow, Reynolds number is

• A. \(2100\)
• B. \(0\)
• C. Infinity
• D. \(100\)

Hint:

An ideal fluid has zero viscosity. Since \(Re=\frac{\rho vD}{\mu}\), Reynolds number tends to infinity.

Answer 1

The Correct Option is C

Reynolds number is defined as: \[ Re=\frac{\rho vD}{\mu}. \] Here: \[ \rho=\text{density}, \] \[ v=\text{velocity}, \] \[ D=\text{characteristic length}, \] and: \[ \mu=\text{viscosity}. \] An ideal fluid is assumed to have zero viscosity. So: \[ \mu=0. \] Now: \[ Re=\frac{\rho vD}{0}. \] This tends to infinity. Therefore, for an ideal fluid flow: \[ Re=\infty. \] Hence, the correct answer is: \[ \text{Infinity}. \]