The maximum thickness of boundary layer in a pipe of radius r is
The thickness of the boundary layer represented, by 8(greek 'delta’) is arbitrarily defined as that distance from the boundary surface in which the velocity reaches 99% of the velocity of the main stream, in a pipe the free stream velocity is at the centre of the pipe. Therefore maximum thickness of boundary layer is r.
The velocity profile for turbulent boundary layer is:
Velocity profile follows 1/7th power law for turbulent boundary layer.
The drag force experienced by an object in a fluid stream is
The correct relationship among displacement thickness ‘d’ momentum thickness ‘m’ and energy thickness ‘e’ is
What is the momentum thickness for the boundary layer with velocity distribution
The momentum thickness is given by,
If x is the distance from leading edge, then the boundary layer thickness in laminar flow varies as
If δ1 and δ2 denote the boundary layer thicknesses at a point distance x from the leading edge on a fiat plate when the Reynolds numbers are 100 and 256 respectively, then the ratio of δ1 to δ2 will be
If δ1 is the thickness of laminar boundary layer at a distance x1 from the leading edge of the flat plate, the thickness δ2 at x2 = 2x1 is equal to
For laminar boundary layer,
The displacement thickness δ* of a boundary layer is defined as δ* =
Separation of boundary layer takes place under