E. Gutmark, H.L. Bowman, K.C. Schadow

The flow field and near field pressure fluctuations of circular and rectangular (AR= 3:1) supersonic (M = 2) jets were measured at a wide range of pressure ratios corresponding to exit Mach number of 1 to 2.5 (after external isentropic expansion). Three rectangular jets, differing by their internal design of the divergence section, were tested. The changes in the internal design had substantial effect on the jet behavior. Typically, the jets exhibited asymmetric flapping mode at their minor axis plane, when operated at off-design conditions. This mode resulted in an enhanced spreading rate. Axis switching was observed in one of the rectangular jets, but the other two showed enhanced growth rate at both axes. The flapping mode instability resulted also in an increased screech level. The asymmetric components of the fluctuations dominated the region upstream of the nozzle exit, while the other modes covered the downstream region. The pressure fluctuations level at the jet edge and the radial decay rate were found to be different at the major and minor axis planes of the different jets and also to vary with the pressure ratio.

DGLR/AIAA 14th Aeroacoustics Conference, 1992

Conference Paper

englisch

21,0 x 29,7 cm, 10 Seiten

DGLR-Bericht, 1992, 1992-03, DGLR/AIAA 14th Aeroacoustics Conference - Proceedings; S.736-745; 1992; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1992