In this case, the modified barrier profile is capable of re-organizing the pressure distribution within the bounded domain and altering the acoustic properties near the top of the sound barrier. Noise barriers alongside roads reduce the traffic sound for houses in the shadow zone. This spreading out is called diffraction. The WTB can alter the sound wave diffraction at the top of the barrier if the wavelengths of the sound wave are comparable or smaller than the dimensions of the wedge. When waves pass through a narrow gap, they spread out. Different kinds of layouts of the walls of the wells. Though they are most often associated with blocking heavy traffic noise. From sky-high walls fencing the length of a busy freeway to barricades surrounding an industrial plant, their composition and functionality vary. Our simulation shows that with a ‘long’ barrier, there’s a lot of reflection of incident energy back towards the source, but although there is some diffraction or bending of the wave around the barrier, this still leaves a zone of silence behind it. Besides, the noise reduction effect relies on the sound diffraction around the top of the barrier, so, the layout of the walls of the wells also plays an important role to improve the performance of the barrier. Sound barriers play an important role in controlling the amount of noise that escapes from a noisy area. These peak pressures usually result in high sound intensity component impinging normal to the barrier surface near the top. And the mainly concerned well should better be located close to the source side. We use a cylindrical coordinate system r,z.The radial distance and angle of the point S with respect to point 1 are r S 1, S 1, etc. It is found that the peak sound pressures in the barrier's shadow zone, which correspond to the minimum values in the barrier's insertion loss, are largely determined by the resonance frequencies and by the shapes and losses of the trapped modes. We consider a barrier whose upper part of length d is inclined toward the source with angle as shown in Fig. At each resonance frequency, a strong and mode-controlled sound field is generated by the noise source both within and in the vicinity outside the region bounded by the sound barrier and the reflecting surface. In this paper, the deterioration in performance of a conventional sound barrier due to the reflecting surface is first explained in terms of the resonance effect of the trapped modes. A wave-trapping barrier (WTB), with its inner surface covered by wedge-shaped structures, has been proposed to confine waves within the area between the barrier and the reflecting surface, and thus improve the performance.
The performance of a sound barrier is usually degraded if a large reflecting surface is placed on the source side.