Sotnikova T. Acoustical properties of noise barrier

This thesis is devoted to study of scattered sound fields created at the noise barriers positioned on the flat ground along the highways. An efficient analytical method for scattered sound field estimation is developed. Based on the results of numerical computations, the detailed analysis of sound fields in wide range of frequencies was carried out, including different barrier dimensions and different combinations of positioning of the sound source and a classic noise reduction barrier, namely the rigid wall. A new, V-shaped design of noise barrier has been proposed. Its enhanced noise reduction efficiency is based on the interferential phenomena near the edge of construction. An efficient analytical method for scattered sound field estimation is developed for the new barrier design. Detailed numerical analysis of sound fields scatted on the V-shaped barrier is conducted over wide range of frequencies and wide set of geometrical configurations of the barrier. The most optimal geometrical configurationof the barrier is determined. Two new integral efficiency criteria for noise barriers are proposed, that may be of high value for practical purposes. A comparative study of the V-shaped and classical barrier was carried out both based on pressure field comparison and based on the proposed integral criteria. Results of comparative analysis showed superiority of noise reduction by a V-shaped barrier over that of a classical one. Recommendations for practical implementation of the barriers involved in the study are developed.