ASA 124th Meeting New Orleans 1992 October

1pEA4. A mechanism of jet--edge interaction and sound radiation.

Youngpil Kwon

Alan Powell

Dept. of Mech. Eng., Univ. of Houston, Houston, TX 77204-4792

A theoretical model is presented to explain the jet--edge interaction and the sound radiation. The aerodynamic response of the edge to the sinuous impinging jet is obtained by regarding the edge reaction as the surface distribution of dipoles necessary to meet the local boundary condition. Then the sound radiation is estimated using these dipoles. The relationship between the jet sinuosity and the sound radiation is quantified: The pressure field on the edge and the directivity of the sound radiation is estimated. It is found that the effective point source is located about a quarter wavelength downstream from the edge tip. The effect of the edge configuration and the jet velocity on the magnitude and directivity of the sound radiation is estimated. This simple model is consistent with available experimental data for low- and high-speed edge tones. [Partial support from Korean Science and Engineering Foundation and the Texas Advanced Research Program.] [sup a)]Permanent address: Dept. of Mech. Eng., Soongsil Univ., Seoul 156, Korea.