Quiet environment: Acoustics of vertical green wall systems of the Islamic urban form

Abstract

The development of sustainability has made the application of green concepts to cityscapes and urban design mandatory and has popularized the installation of vegetation on external street walls. Introducing greenery on external building elements is beneficial to the environment, reducing the heat impact experienced in “urban heat islands” and enhancing an area's visual effect. The popularity of such green systems has necessitated the assessment of their acoustic characteristics and their impact on long-distance noise propagation. These effects become important in hot climates, where the topology of the dense urban texture gives building walls larger areas than exposed streets, thereby amplifying the effects of the former's acoustic characteristics on noise levels. Considering the resultant sound level at a particular location between buildings as the contribution of several remote sources, a simplified computer model based on energy exchange is developed in this study. Owing to the complexity of the urban landscape, buildings are assumed to be an array of rectangular blocks. The computer model is used to investigate the effects of the installation of street vertical vegetation on long-distance noise propagation, as well as those of the geometric parameters of the dense Islamic urban texture on the resultant noise levels.

Key words： Acoustics; Green walls; Sound propagation; Acoustic computer simulation