Aerodynamic Internal Pressure Loads Applied On Nonstructural Elements under Wind Gusts

Vent holes can be used to reduce the aerodynamic pressure loads on nonstructural elements of buildings. The analysis of these loads applied on nonstructural elements of buildings (window panes, closure panels, etc.) with vent holes, under gusty wind conditions, have been studied both experimentally and employing a theoretical model. An experimental setup based on an open circuit, closed test section, and low speed wind tunnel, designed and built at the Instituto de Microgravedad “Ignacio Da Riva” of the Universidad Politécnica de Madrid (IDR/UPM) has been used. A mechanism in the wind tunnel generates sinusoidal gusty winds inside the test section. Theoretical predictions of the pressure loads have been obtained using a mathematical model based on the mass conservation equation and polytropic law gas evolution. In the experimental setup, an air reservoir with a vent hole has been selected as a model to simulate the internal pressure loads acting on the walls of a building under a tangential unsteady (gusty) flow. The pressure jumps developed across the vent holes have been studied as a function of vent hole size, air reservoir volume, and gust frequency. In this work, the results for the case of small pressure jumps across the vent hole have been presented, which is the case of most practical interest, in order to reduce the pressure load on the elements.The evolution of the pressure loss coefficient ξ, at unsteady flow conditions has been studied, and it has been found that its value is not constant in a gusty wind, but depends both on the frequency of the gust and on the direction of the flow through the vent hole (either inhalation or exhalation).