Why The Term “Sound Barrier” Is Important For Aeronautical Engineers?
The term “sound barrier” is not a right way to describe a condition that exists when planes travel at certain speeds. A kind of barrier was expected when planes reached the speed of sound, but no such barrier developed. In order to understand this let’s start with a plane travelling at ordinary low-speed flight. As the plane moves forward, the front parts of the plane send out a pressure wave. The pressure wave is caused by the building up of particles of air as the plane moves forward. Now this pressure wave goes out ahead of the plane at the speed of sound. It is, therefore, moving faster than the plane itself, which, as we said, is moving at ordinary speed. As this pressure wave rushes ahead of the plane, it causes the air to move smoothly over the wing surfaces of the approaching plane. Now let’s say the plane is travelling at the speed of sound. The air ahead receives no pressure wave in advance of the plane, since both the plane and the pressure wave are moving forward at the sam
