Question

The displacement thickness of a boundary layer is

• A. the distance to the point where (v/V) =0.99
• B. The distance where the velocity 'v' is equal to the shear velocity V, that is, where v=V.
• C. the distance by which the main flow is to be shifted from the boundary to maintain the continuity equation
• D. one half the actual thickness of the boundary layer

Answer 1

The correct option is C the distance by which the main flow is to be shifted from the boundary to maintain the continuity equation

The displacement thickness of a boundary layer is the distance by which main flow should be shifted in order to compensate for decrease in velocity in the boundary layer and to maintain the continuity equation.