Revision : Basic Aerodynamics

In which atmospheric layer is the temperature assumed to be constant at -56.5°C?

• Ionosphere

• Lower stratosphere

• Troposphere

Humidity is a condition of moisture and dampness. With the increase in temperature, the humidity will

• increase

• decrease

• be unaffected

Aircraft design ensures that turbulent flow on top of the wing is limited to a minimum, so that

• the drag can be reduced

• the stall angle can be increased

• the lift coefficient can remain constant

How does the air flow behave when passing through a convergent / divergent duct?

• The airflow accelerates as it leaves the throat

• The airflow accelerates as it enters the throat

• The airflow decelerates as it enters the throat

The first layer of the Boundary Layers which is in contact with the airfoil surface is static. In the upper layers, the velocity of air increases. This is effect is due to:

• A greater pushing force from relative wind

• The viscosity of the air

• The compression of upper layers of air

Viscosity is defined as

• The tendency of one layer of fluid to stick to the next layer, preventing relative motion

• Friction due to roughness of the surface, preventing relative motion

• A property of air flow to become turbulent at higher speeds

Which of the following explains the effect of aileron reversal?

• The aircraft tends to yaw in the opposite direction

• The aircraft tends to roll in the opposite direction

• The aircraft tends to pitch in the opposite direction

The point at which the relative airflow separates into two paths at the leading edge of

the airfoil is known as the:

• Transition point.

• Separation point

• Stagnation point

In the equation for Lift (L = ½ ρ V² C_L S), which variables indicate the dynamic pressure?

• ½ ρ V²

• C_L S

• V² S

If ‘Fineness Ratio’ of a wing is 25%, what does the 25% indicate?

• the thickness of the wing span

• . the chord length of wing’s length

• the thickness of total chord length of a wing