11.1 Pressure, Heating & Area Rule

Question 1

What happens when aircraft reaches speed of sound ?

Answer 1

Pressure waves cannot get away and begin to compress and accumulate

Question 2

What happens when aircraft speed goes over the speed of sound ?

Answer 2

It overtakes pressure waves and they radiate behind it

Question 3

What limits the speed of the aircraft in oblique shock waves ?

Answer 3

The bow wave forming at the leading edge of a wing traps a section of air on the leading edge

Question 4

What is the purpose of a supersonic aero foil ?

Answer 4

The leading edge is sharp or pointed
The bow wave can then attach to the leading edge and slope backwards to form an oblique shock wave

Question 5

What is an expansion wave ?

Answer 5

Expansion wave is formed when supersonic airflow changes direction around a curve or a corner, away from the preceding flow direction

Question 6

What does an expansion wave not do ?

Answer 6

Does not cause sharp or sudden changes in airflow
As it changed direction it expands accelerates and follows the contour of the surface