Interaction of Sound from Supersonic Jets with Nearby Structures

A model of sound generated in an ideally expanded supersonic (Mach 2) jet is solved numerically. Two con gurations are considered; (i) a free jet and (ii) an installed jet with a nearby array of exible aircraft type panels. In the later case the panels vibrate in response to loading by sound from the jet and the full coupling between the panels and the jet is considered, accounting for panel response and radiation. The long time behavior of the jet is considered. Results for near eld and far eld disturbance, the far eld pressure and the vibration of and radiation from the panels are presented. Panel response crucially depends on the location of the panels. Panels located upstream of the Mach cone are subject to a low level, nearly continuous spectral excitation and consequently exhibit a low level, relatively continuous spectral response. In contrast, panels located within the Mach cone are subject to a signi cant loading due to the intense Mach wave radiation of sound and exhibit a large, relatively peaked spectral response centered around the peak frequency of sound radiation. The panels radiate in a similar fashion to the sound in the jet, in particular exhibiting a relatively peaked spectral response at approximately the Mach angle from the bounding wall. Supported by NASA Langley Research Center while in residence under a National Research Council Postdoctoral Research Associateship Award. Partially supported by NASA Langley Research Center under contract NAS1-19480 while in residence at ICASE. Additional support was provided by NSF grants DMS 93-01635 and DMS 95-30937.