Effect Of Cross-wire And Tabs On Sonic Jet Structure
Published 2007 · Physics
An experimental study has been conducted to investigate the effectiveness of passive controls in the form of small tabs and a cross-wire projecting normally into the flow at the nozzle exit, on the characteristics of an axisymmetric sonic jet operated at three underexpansion levels. In this investigation, NPR 3, 5 and 7 were studied. The cross-wire and tabs were found to reduce the amplitude and axial extent of Pitot pressure oscillations and also the supersonic core length. Both cross-wire and tabs were found to be effective in modifying the jet structure significantly, resulting in faster characteristic decay of the jet at all the NPRs. Shadowgraph pictures captured the widening of the supersonic zone in the direction normal to the tabs/cross-wire.