Day 42-Nov 1-Worksheet-Diploma-Boundary layer theory

In the boundary layer, velocity becomes 99 % of free-stream velocity at a distance known as —

The velocity profile in a laminar boundary layer is —

In turbulent boundary layer, the velocity distribution is approximately —

• Linear

• Logarithmic

• Uniform

• Parabolic

At what Reynolds number does laminar flow generally become turbulent on a flat plate?

• Re = 2 × 10⁴

• Re = 5 × 10⁵

• Re = 10⁶

• Re = 10⁷

Which of the following layers exists within the turbulent boundary layer due to high viscous effects?

• Transition layer

• Outer layer

• Laminar sub-layer

• Wake region

In a laminar flow over a flat plate, boundary-layer thickness (δ) varies with distance x as —

• δ ∝ x¹/⁵

• δ ∝ x¹/²

• δ ∝ x

• δ ∝ x²

Boundary-layer separation occurs when —

• ∂u/∂y > 0

• ∂u/∂y = 0

• ∂u/∂y < 0

The region near the solid boundary where viscous effects dominate is called __________.

The displacement thickness represents the distance by which the __________is displaced away from the wall due to boundary layer.

The ratio of displacement thickness to momentum thickness is called __________.