Proceedings of the KSME Conference (대한기계학회:학술대회논문집)
- 2004.04a
- /
- Pages.2023-2028
- /
- 2004
An Experimental Study on the Screech Tone in Supersonic Jet
초음속 제트의 스크리치 톤에 관한 실험적 연구
- Published : 2004.04.28
Abstract
The effects of nozzle-lip thickness on the relationship between screech tone and broadband shock-associated noise were experimentally investigated using a convergent-divergent nozzle with a design Mach number of 2.0. Overall sound pressure levels (OASPL) and noise spectra were obtained at far-field locations. Schlieren optical system was used to visualize the flow-fields of supersonic jets. A baffle plate was installed at the exit of the nozzle and its size was varied to obtain different nozzle-lip thicknesses. Experiment was carried out over a wide range of nozzle pressure ratios from 2.0 and 18.0, which corresponds to over- and under-expanded conditions. The results obtained clearly show that the screech tones are influenced by the nozzle-lip thickness. It is found that the screech tone and its peak amplitude are strongly dependent on whether the jet is over-expanded and under-expanded at the nozzle exit.
Keywords