Analysis of a pressure equalized rainscreen wall as a periodic array of Helmholtz resonators.

Abstract

One of the primary purposes of the building enclosure is to separate occupants from the natural elements such as rain and snow. Water can penetrate this enclosure through four primary mechanisms: air pressure differences between interior and exterior, rain drop momentum, surface tension, and capillary action. The pressure equalized rainscreen (PER) wall is a two layer wall construction that places a vented cavity between an inner wall and outer cladding. When properly designed, the cavity pressure equalizes to that of the external wind on the building, keeping rain from entering the cavity by air pressure differences and the cavity space eliminates momentum, surface tension, and capillary action as water transport mechanisms. A typical building using PER walls will have a large number of these cavities with a regular spacing. In this paper the wind response of the PER wall will be analyzed as a periodic array of Helmholtz resonators exposed to periodic excitation.