ESDU 74033 gives a method based on a statistical, theoretical treatment incorporating the characteristics of the shock waves generated by the fan. A set of curves enables the components of sound pressure level to be obtained; the first graph gives the component depending on distance upstream of the compressor and the pressure in the duct, the second gives a component depending on the Mach number at the fan, the third gives the component depending on the shock-wave characteristics and guidance on appropriate values for these is provided, and the fourth defines the envelope of the peaks of the tone spectrum and must be evaluated for each tone considered. Finally a curve defines the cut-off frequency below which tones do not effectively propagate along the duct. The method is programmed and referred to as ESDUpac A7433.
| IHS ESDU | |
|---|---|
| Product Category | Standards and Technical Documents |
| Product Number | 74033 |
| Product Name | Estimation of sound pressure levels due to buzz-saw noise within the intake duct of a supersonic fan or compressor. |
