$sound diffraction$

11-2B except that the aperture is very small and only a small amount of energy passes through it. 11-2A, each wavefront passing through the aperture becomes a row of point sources radiating diffracted sound into the shadow zone. The sound energy at any point in the shadow zone can mathematically be obtained by summing the contributions of all of these point sources on the wavefronts. Huygens' principle can be paraphrased as:Įvery point on the wavefronts of sound that has passed through an aperture or passed a diffracting edge is considered a point source radiating energy back into the shadow zone. The same principle also gives a simple explanation of how sound energy is diverted from the main beam into the shadow zone. (B) If the aperature is small compared to the wavelength of the sound, the small wavefronts which do penetrate the hole act almost as point sources, radiating a hemispherical field of sound into the shadow zone.įor an answer, the work of Huygens is consulted.1 He enunciated a principle that is the basis of very difficult mathematical analyses of diffraction. These wavefronts act as lines of new sources radiating sound energy into the shadow zone. (A) An aperature large in terms of wavelength of sound allows wavefronts to go through with little disturbance. By what mechanism is this diversion accomplished? The arrows indicate that some of the energy in the main beam is diverted into the shadow zone.

$sound diffraction$

The wavefronts of sound strike the heavy obstacle: some of it is reflected, some goes right on through the wide aperture. Figure 11-2A illustrates the diffraction of sound by an aperture that is many wavelengths wide.

$sound diffraction$

Sound diffraction