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Measurement of far field combustion noise from a turbofan engine using coherence functions
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Karchmer, A. M. Montegani, F. J. Reshotko, M. |
| Copyright Year | 1977 |
| Description | Coherence measurements between fluctuating pressure in the combustor of a YF-102 turbofan engine and far-field acoustic pressure were made. The results indicated that a coherent relationship between the combustor pressure and far-field existed only at frequencies below 250 Hz, with the peak occurring near 125 Hz. The coherence functions and the far-field spectra were used to compute the combustor-associated far-field noise in terms of spectra, directivity, and acoustic power, over a range of engine operating conditions. The acoustic results so measured were compared with results obtained by conventional methods, as well as with various semiempirical predictions schemes. Examination of the directivity patterns indicated a peak in the combustion noise near 120 deg (relative to the inlet axis). |
| File Size | 8085176 |
| Page Count | 33 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19770026219 |
| Archival Resource Key | ark:/13960/t8bg7gj9w |
| Language | English |
| Publisher Date | 1977-10-05 |
| Access Restriction | Open |
| Subject Keyword | Aircraft Propulsion And Power Jet Aircraft Noise Combustion Stability Coherence Coefficient Far Fields Acoustic Propagation Turbofan Engines Inlet Flow F-102 Aircraft Noise Measurement Noise Spectra Pressure Gradients Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
