Velocity distribution downstream of an asymmetric wide-angle diffuser

LDV and wall static pressure measurements were performed to investigate the flow properties downstream of an asymmetric wide-angle diffuser controlled by perforated plates. The experimental results showed significant changes in the mean flow velocity and local fluctuating component properties downstream of the diffuser. The tests were undertaken in a system comprising half a conventional pyramidal diffuser connected to a chamber of rectangular cross-section. One of the lateral walls was parallel to the flow, and the opposite one had an opening angle of 45°. The total diffuser opening vertical angle delimited by the top and bottom walls was 60°, and the area ratio was equal to 7. A combination of four perforated plates with porosities of 45%, positioned within the diffuser, permitted the investigation of a total of seven different experimental configurations. While good flow uniformity could be achieved in symmetric diffusers with only two perforated plates, as reported in the literature, it has been found that an additional plate is needed for the best flow distribution in the studied asymmetric diffuser.