The paper presents the results of a theoretical study into the effects of u
nsteady wind pressures on the instantaneous flow rates in certain types of
purpose-designed naturally ventilated buildings. The study used nondimensio
nal parameters and the results should therefore cover a wide range of condi
tions and should be of general application. The main concern is with the po
tential for reducing the occurrence of instantaneous flow reversal through
openings, by the use of long ducts instead of sharp-edged openings. It is c
oncluded that substantial benefits can be achieved and the required conditi
ons are defined in nondimensional terms. (C) 2000 Elsevier Science Ltd. All
rights reserved.