AN EXPERIMENTAL INVESTIGATION OF THE AEROACOUSTICS OF A TWO-DIMENSIONAL BIFURCATED SUPERSONIC INLET

✍ Scribed by S.-M. LI; C.A. HANUSKA; W.F. NG

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 501 KB
• Volume: 248
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.2001.3731

✦ Synopsis

An experiment was conducted on a two-dimensional bifurcated, supersonic inlet to investigate the aeroacoustics at take-o! and landing conditions. A 104)1 mm (4)1 in) diameter turbofan simulator was coupled to the inlet to generate the noise typical of a turbofan engine. Aerodynamic and acoustic data were obtained in an anechoic chamber under ground-static conditions (i.e., no forward #ight e!ect). Results showed that varying the distance between the trailing edge of the bifurcated ramp of the inlet and the fan face had negligible e!ect on the total noise level. Thus, one can have a large freedom to design the bifurcated ramp mechanically and aerodynamically, with minimum impact on the aeroacoustics. However, the e!ect of inlet guide vanes' (IGV) axial spacing to the fan face has a "rst order e!ect on the aeroacoustics for the bifurcated 2-D inlet. As much as 5 dB reduction in the overall sound pressure level and as much as 15 dB reduction in the blade passing frequency tone were observed when the IGV was moved from 0)8 chord of rotor blade upstream of the fan face to 2)0 chord of the blade upstream. The wake pro"le similarity of the IGV was also found in the #ow environment of the 2-D bifurcated inlet, i.e., the IGV wakes followed the usual Gauss' function.