Shear velocity isa)a non-dimensional quantityb)a convenient fictious quantityc)the velocity of fluid at the edge of laminar sublayerd)the velocity of fluid at the edge of roughnessCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Answer

We consider shear velocity when Flow in pipe is turbulent.
basically it's used to represent avg velocity with friction factor as a cumulative term.

Answer

Shear velocity is a term commonly used in fluid mechanics to represent the velocity of fluid at the edge of the laminar sublayer or the edge of roughness. However, the correct answer to this question is option 'B': a convenient fictitious quantity.

Explanation:
- Shear velocity, also known as friction velocity, is a concept used in fluid dynamics to describe the velocity at which a fluid layer adjacent to a solid surface undergoes shear stress.
- It is a non-dimensional quantity because it is expressed as a ratio of the square root of the shear stress to the fluid density.
- The shear velocity can be defined mathematically as u*_s = sqrt(tau / rho), where u*_s is the shear velocity, tau is the shear stress, and rho is the fluid density.
- The laminar sublayer is a thin layer of fluid near a solid boundary where the flow is highly influenced by viscous effects. The velocity at the edge of this sublayer is often approximated as the shear velocity.
- Similarly, the edge of roughness refers to the point where the boundary layer transitions from a smooth surface to a rough surface, and the velocity at this edge can also be represented by the shear velocity.
- Therefore, although options 'C' and 'D' are valid descriptions of the shear velocity, they are not the correct answer to the question.
- The correct answer, option 'B', implies that shear velocity is a fictitious quantity that is used conveniently in fluid mechanics to represent the velocity at the edge of the laminar sublayer or roughness.
- It is a useful concept because it allows engineers and researchers to simplify calculations and analyze fluid flow near solid boundaries without the need for complex modeling of the boundary layer.

Top Courses for Mechanical EngineeringView all

GATE Mechanical (ME) Mock Test Series 2026

Crash Course: Mechanical Engineering (ME)

Strength of Materials (SOM)

Fluid Mechanics for Mechanical Engineering

General Aptitude for GATE

Top Courses for Mechanical Engineering

Top Courses for Mechanical Engineering

Related Content

Mock Test Series

Subject-wise Courses

Subject-wise Courses

Other Engg Branches

Company