Presentation and verification of a simple mathematical model foridentification of the areas behind noise barrierwith the highest performance

Background and aims Traffic noise barriers are the most important measure to control the environmental noise pollution. Diffraction from top edge of noise barriers is the most important path of indirect sound wave moves towards receiver.Therefore, most studies are focused on improvement of this kind. Methods T-shape profile barriers are one of the most successful barrier among many different profiles. In this investigation the theory of destructive effect of diffracted waves from real edge of barrier and the wave diffracted from image of the barrier with phase difference of radians is used. Firstly a simple mathematical representation of the zones behind rigid and absorbent T- shape barriers with the highest insertion loss using the destructive effect of indirect path via barrier image is introduced and then two different profile reflective and absorption barrier is used for verification of the introduced model Results The results are then compared with the results of a verified two dimensional boundary element method at 1/3 octave band frequencies and in a wide field behind those barriers. Avery good agreement between the results has been achieved. In this method effective height is used for any different profile barriers. Conclusion The introduced model is very simple, flexible and fast and could be used for choosing the best location of profile rigid and absorptive barriers to achieve the highest performance