Civil Engineering - GATE Exam Questions - Discussion


The flow of water (mass density = 1000 kg/m3 and kinematic viscosity = 10-6 m2/s) in a commercial pipe, having equivalent roughness ks as 0.12 mm, yields an average shear stress at the pipe boundary = 600 N/m2. The value of ks/δ' (δ' being the thickness of laminar sub-layer) for this pipe is

[A]. 0.25
[B]. 0.50
[C]. 6.0
[D]. 8.0

Answer: Option D


No answer description available for this question.

Suresh said: (May 25, 2017)  
Anyone explain it.

Ajay said: (Sep 9, 2018)  
Laminar sub-layer thick = 11.6 * kinematic viscosity/shear velocity.

Shear velocity =(shear stress /density of fluid)^0.5.

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