What Is The Barrier Of Sound?

The name “sound barrier” is actually a wrong way to describe a condition that exists when planes travel at a particular speed. When the speed of sound is attained, a kind of barrier is expected, in actual no barrier developed.

Take a plane traveling at a slow speed. With the forward movement of the plane, the front parts send out a pressure wave, which is caused by the building up of particles of air.

Now the pressure wave goes out ahead of the plane at a speed of sound and is therefore moving faster than the speed of the plane, which is ordinary low. This pressure wave rushes ahead of the plane and causes smooth movement of air over the wing surface of the approaching plane.

Now in another case, the plane is traveling at sound’s speed. The air ahead receives no pressure wave in advance of the plane. The speed of the plane and pressure wave moving forward is the same and thus the pressure wave builds up in front of the wing.

The result is a shock wave, that creates great stresses in the plane wings. Before the plane actually flew at the speed of sound and faster, it was expected that these shock waves and stresses would create a kind of ‘barrier’, for the plane a ‘sound barrier. In actual it did not develop as the aeronautical engineers were able to design planes to overcome it.

A loud ‘boom’ is heard when a plane passes through the sound barrier and is caused by the shock waves. These shock waves develop when the speed of the plane and the pressure wave is the same.