The observation of wind pressure acting on the wall and floor of a full-scale building model under cross ventilation was carried out. The measurement of air flow was also undertaken, and the existing prediction theory of the air flow rate, namely the orifice flow equation, including the discharge coefficient, was evaluated for its accuracy. At the same time, a method of predicting the discharge coefficient has been proposed and tested.
Wind pressures can significantly affect ventilation performance. However often they are overlooked in the design of a naturally ventilated building, with buoyancy forces presumed to offer the worst case scenario for design. The result is that airflow patterns and the ventilation performance of the building is often different from the design intent. Successful natural ventilation design requires careful consideration of the building form, and so must involve the architect at the early stages of fabric development.
A computer program has been developed to predict the wind pressure coefficients Cp on facades and roofs of block shaped buildings. The program is based on fits of measured data, including wind shielding by obstacles and terrain roughness. Main advantages of the program are: - it needs no expertise of its users on wind pressures; - the input is simple. It exists of building and obstacles coordinates and orientations; - generating Cp values for ventilation model calculations needs no separate action.
The Air Infiltration and Ventilation Centre s Numerical Database has been developed in response to a need to establish a core of numerical data suitable for design purposes and model validation. It has also been developed to provide a focus for
Tall buildings can deflect high-level wind down towards the ground, producing unpleasant and sometimes dangerous winds in adjoining pedestrian areas. Architects, planners and developers must aim to provide safe and comfortable conditions in open-air pedestrian areas; they should, therefore, understand how the wind flows around buildings and how to control it by good design.
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