What is the relationship between velocity boundary layer and thermal boundary layer?

What is the relationship between velocity boundary layer and thermal boundary layer?

If the Prandtl number is less than 1, which is the case for air at standard conditions, the thermal boundary layer is thicker than the velocity boundary layer. If the Prandtl number is greater than 1, the thermal boundary layer is thinner than the velocity boundary layer.

What are the velocity and thermal boundary layers under what conditions do they develop?

Under what conditions do the velocity boundary layers develop? The velocity boundary layer develops whenever there is fluid flow over a surface. Results from a difference between free stream velocity and the zero velocity at the wall Important to convection transfer.

What is the process of formation of boundary layers on flat plate?

This condition states that the velocity of the fluid at the solid surface equals the velocity of that surface. The result of this condition is that a boundary layer is formed in which the relative velocity varies from zero at the wall to the value of the relative velocity at some distance from the wall.

Why does boundary layer separate?

The phenomenon is termed as separation of boundary layer. Separation takes place due to excessive momentum loss near the wall in a boundary layer trying to move downstream against increasing pressure, i.e., , which is called adverse pressure gradient.

What is the range of Reynolds Number?

Whenever the Reynolds number is less than about 2,000, flow in a pipe is generally laminar, whereas, at values greater than 2,000, flow is usually turbulent.

Is laminar or turbulent flow better?

Under turbulent flow conditions, the increase in heat transfer rate is more significant than that under laminar flow conditions. This is due to the increase in the Reynolds number of the flowing fluid in turbulent flow. The turbulent effects become a dominant factor over secondary flow at higher Reynolds number.