Bow wave, progressive disturbance propagated through a fluid such as water or air as the result of displacement by the foremost point of an object moving through it at a speed greater than the speed of a wave moving across the water.

Diffraction: A wave encountering a small obstacle tends to bend around the obstacle. This bending of the wavefront is called diffraction. When a wave encounters a barrier with an aperture, which is much smaller than the wavelength, the wave bends and spreads out as a spherical circular wave.

When the source moves at a speed equal to the speed of the wave, a barrier wave is produced in front of the source as each successive wave front piles on top of the previous one. The width of the bow wave or shock cone depends on the speed of the source; the faster the source travels, the narrower the wave becomes.

Normal Shocks Shock waves are highly localized irreversibilities in the flow . Within the distance of a mean free path, the flow passes from a supersonic to a subsonic state, the velocity decreases suddenly and the pressure rises sharply.

How does the V shape of a bow wave depend on the speed of the source? The angle of the V gets smaller as the speed of the source gets faster. A bow wave on the surface of water is two-dimensional. What about a shock wave in air?

A bow wave is a v-shaped disturbance created by an object moving across a liquid surface at a speed greater than the wave speed but a shock wave is a cone-shaped disturbance created by an object moving at supersonic speed through a fluid. What is a sonic boom?

The source of all wave motion is a disturbance in matter or a vibration.