Unsteady flow effects due to fluctuating wind pressures in natural ventilation design—mean flow rates

The paper presents the results of a study into the effects of unsteady wind pressures on the mean flow rates in certain types of purpose-designed naturally ventilated buildings. The study used nondimensional parameters and the results should therefore cover a wide range of conditions and should be of general application. It is concluded that unsteady effects are restricted to a relatively narrow band of conditions. These conditions have been quantified in terms of nondimensional parameters. In particular a simple procedure for calculating the mean flow rates when the unsteady effects are large has been derived. In its simplest form the procedure does not require knowledge of the instantaneous wind pressures.