Numerical and experimental study on noise shielding effect of eaves/louvers attached on building façade

•We examined noise reduction effects by eaves and louvers attached on building façade.•We made numerical analysis using the finite-difference time-domain method.•We made a 1/20 scale model experiment to validate the numerical analysis.•Flat and inclined eaves, louvers with short fins were examined by numerical analysis.•Inclined type eaves are effective for noise reduction especially at high story.

Recently, high-rise buildings located in urban area of Japan have eaves on their façade. The eaves are regarded as an efficient measure for mitigating environmental loads by solar radiation heat. The eaves are also utilized to introduce sunlight into the rooms and they contribute energy saving. Besides that, the eaves can be an efficient countermeasure for reduction of traffic noise. On the noise reduction effects by eaves/louvers attached on building façade, numerical analyses and a scale model experiment were performed. Three dimensional numerical analysis of outdoor sound propagation generally takes huge computational costs. To relieve the computational costs, 2-D to 3-D Fourier-like transformation technique based on 2-D finite-difference time-domain analysis was employed in this study. Comparison between flat type eaves, inclined type eaves and louvers consisting of short fins revealed that the inclined type eaves are effective as a noise reduction measure.