Abstract
An experimental investigation of flow unsteadiness occurring in regular pyramidal diffusers has been done using air as the working fluid. This report is shown that the average flow pattern in cross section across outlet flow of the diffuser, in which unsteadily flow is visualized by tuft grid method, and by using the photographic film and video imaging. The diffusers are presented for following condition: length ratio=10 and total divergence angles= 2, 4, 6, 8, 10, 12 degree. The total tuft length is 6.5mm. Visualization results clearly show the change of flow pattern between the different divergence angles. These results were compared to the spectrums of total pressure.
