Question

For turbulent flow, the value of Reynolds number is:

• A. $R_e<2000$
• B. $R_e>2000$
• C. $1000<R_e<2000$
• D. $R_e=1000$

Answer 1

Answer: (B)

$R_e>2000$

Reynolds number is the non-dimensional number consisting of the velocity scale and length scale. It is a product of the velocity scale and the length scale over the kinematic viscosity.

Reynolds number is the ratio of the inertia force and viscous force. It is the key parameter to determine whether or not flow is laminar or turbulent. At Reynolds numbers between about 2000 and 4000, the flow will be unstable as a result of the turbulence.

Option B is correct.