Diffraction determines the direction in which most sound will be radiated, an important factor for the acoustical engineers who work to make them as quiet as possible. The white region is a cross-section of the front part of an aircraft engine, the sound wave is produced by the turbofan. The animation below shows another example of diffraction. Thus, this solution for noise reduction is efficient only if the houses are located within the shadow region of the sound barrier. It is characterised by low noise levels due only to the acoustic diffracted wave. This means the sound wave arrives slightly later and is altered in terms of the. Sound to the furthest ear has to diffract (bend) around the head. When sound comes from the side (directly, or via a reflection as shown in the picture), the sound at each ear is different. A shadow region is observed just behind the barrier (bottom right of the animation). Your brain uses this information to locate the sound in front of you. Interference patterns due to the superposition of the incident wave and the diffracted wave are clearly seen just before the barrier (bottom left of the animation). The animation below illustrates how a travelling wave emitted from the upper left corner by, say, an aeroplane is diffracted by a sound barrier erected to shield homes from the traffic noise. 110 - Wave DiffractionIn this video Paul Andersen explains how waves will diffract (or bend) around an obstacle or while traveling through and opening. An example of diffraction phenomena is given by the spreading of waves around an obstacle. Diffraction of sound refers to the bending or spreading of sound waves as they encounter obstacles or pass through openings in a barrier. Diffraction occurs if a wave encounters an object and if the wavelength is of the same size (or greater than) the object size. The spreading of waves when they pass through an opening, or around an obstacle into regions where we would not expect them, is called diffraction.
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