Question

In a fluid flowing over a flat plate, the Reynolds number (Re) determines:

• A. The rate of mass transfer
• B. Whether the flow is laminar or turbulent
• C. The pressure drop in the fluid
• D. The temperature distribution

Hint:

Reynolds number gives insight into flow behavior—low \(Re\) implies smooth (laminar) flow, high \(Re\) implies chaotic (turbulent) flow.

Answer 1

The Correct Option is B

The Reynolds number (\(Re\)) is a dimensionless quantity used in fluid mechanics to predict the flow regime in a fluid system.
It is defined as: \[ Re = \frac{\rho v L}{\mu} \] Where:
\(\rho\) = fluid density, \(v\) = flow velocity, \(L\) = characteristic length, \(\mu\) = dynamic viscosity
- When \(Re<2000\), the flow is typically laminar.
- When \(Re>4000\), the flow is typically turbulent.
- The range in between is considered transitional.
Thus, Reynolds number helps determine whether the fluid flow is laminar or turbulent.