Correct Answer - Option 3 : logarithmic law
Explanation:
Velocity Distribution for Turbulent Flow in pipes.
Prandtl’s universal velocity distribution equation.
\(v = {v_{max}} + 2.5{V^*}{\log _e}\left( {\frac{y}{R}} \right)\)
Where, \({V^*} = \sqrt {\frac{{{\tau _0}}}{\rho }} = Shear\;or\;friction\;velocity.\)
y = distance from the pipe wall
ρ = Density of fluid.
On observing the above equation we can say that velocity distribution in the turbulent boundary layer follows logarithmic law.
The above equation is valid for both smooth and rough pipes.