Optimization of Profiled Diffuser Barrier Using the New Multi-impedance Discontinuities Model

The paper describes an investigation about the application of the new multiple-impedance discontinuities model for optimizing profile diffuser barriers. The new multiple-impedance discontinuities model is much faster than the numerical method, thus it is used in an optimization process. The A-weighted insertion loss was used for the traffic noise spectrum. The result of optimization, which is done by simplex downhill method, showed that the chosen method combined with the appropriate cost function is both a fast and effective way to optimize a diffusive profiled barrier, improving the performance of the barrier in the whole frequency bandwidth of the reactive profiled barriers. The optimized barrier improves the A-weighted insertion loss of all different tested barriers including absorbent, quadratic residue sequence and random sequence barriers.The introduced optimization process in this investigation is fast, clear and flexible so that any different ribbed surfaces and dimensions utilized on any different T-profile barriers can be optimized. The parameter used to optimize is just simply the well depth sequence, which is easy to realize and practical to design.