Modeling pressure equalization in cavities

Wind loads on the outerblades of facades and rain penetration can be reduced by pressure equalization (PE). PE is in principle a dynamical, non-linear process. In this paper a first order one zone model is presented. A test setup has been developed which consists of a cavity with perforated blades. The openings in the blades are standard-edged circular orifices and it is possible to vary them together with the volume of the cavity. PL feature of non-linear systems is that the response of the sum of two input signals does not equal the sum of the two output responses. Therefore, transfer functions are dependent on the input signal. The measurements show an agreement with the applied model. Scaling factors for measurements and simulation on different geometries are suggested. The graphical output of the used scaled parameters shows a geometry independent curve, which can be used as a design tool for PE. (C) 1998 Elsevier Science Ltd. All rights reserved.