Loading...
Please wait, while we are loading the content...
Similar Documents
Jet surface interaction scrubbing noise from high aspect-ratio rectangular jets
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Bozak, Richard F. Khavaran Sr., Abbas |
| Copyright Year | 2015 |
| Description | Concepts envisioned for the future of civil air transport consist of unconventional propulsion systems in the close proximity of the airframe. Distributed propulsion system with exhaust configurations that resemble a high aspect ratio rectangular jet are among geometries of interest. Nearby solid surfaces could provide noise shielding for the purpose of reduced community noise. Interaction of high-speed jet exhaust with structure could also generate new sources of sound as a result of flow scrubbing past the structure, and or scattered noise from sharp edges. The present study provides a theoretical framework to predict the scrubbing noise component from a high aspect ratio rectangular exhaust in proximity of a solid surface. The analysis uses the Greens function (GF) to the variable density Pridmore-Brown equation in a transversely sheared mean flow. Sources of sound are defined as the auto-covariance function of second-rank velocity fluctuations in the jet plume, and are modeled using a RANS-based acoustic analogy approach. Acoustic predictions are presented in an 8:1 aspect ratio rectangular exhaust at three subsonic Mach numbers. The effect of nearby surface on the scrubbing noise component is shown on both reflected and shielded sides of the plate.|||||||||||| |
| File Size | 6212423 |
| Page Count | 24 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20150010713 |
| Archival Resource Key | ark:/13960/t3130w917 |
| Language | English |
| Publisher Date | 2015-04-21 |
| Access Restriction | Open |
| Subject Keyword | Propulsion Noise Jet Noise Jet Surface Interaction High Aspect Ratio Green's Functions Subsonic Speed Jet Aircraft Noise Noise Reduction Shear Flow Aerodynamic Noise Propulsion System Configurations Plumes Analogies Solid Surfaces Airframes Surface Reactions Turbulence Models Trailing Edges Noise Pollution Jet Exhaust Mach Number Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Presentation |
