On the Existence of Subharmonic Screech in Choked Circular Jets from a Sharp-Edged Orifice - Open Journal of Acoustics

OJA > Vol.4 No.1, March 2014

On the Existence of Subharmonic Screech in Choked Circular Jets from a Sharp-Edged Orifice ()

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DOI: 10.4236/oja.2014.41003 2,999 Downloads 4,732 Views Citations

Author(s)

Max Kandula

Affiliation(s)

ESC-Team QNA, NASA Kennedy Space Center, USA.

ABSTRACT

Experiments are performed in choked circular hot and cold nitrogen jets issuing from a 2.44 cm diameter sharp-edged orifice at a fully expanded jet Mach number of 1.85 in an effort to investigate the character of screech phenomenon. The stagnation temperature of the cold and the hot jets are 299 K and 319 K respectively. The axial distribution of the centerline Mach number was obtained with a pitot tube, while the screech data (frequency and amplitude) at different axial and radial stations were measured with the aid of microphones. The fundamental screech frequency of the hot jet is slightly increased relative to that of the cold jet. It is concluded that temperature effects on the screech amplitude are manifested with regard to the fundamental and the subharmonic even at relatively small temperature range considered.

KEYWORDS

Subharmonic Screech; Sharp-Edged Orifice; Circular Jets; Thermal Effects

Share and Cite:

Kandula, M. (2014) On the Existence of Subharmonic Screech in Choked Circular Jets from a Sharp-Edged Orifice. Open Journal of Acoustics, 4, 20-25. doi: 10.4236/oja.2014.41003.

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