Organized motions in a plane turbulent jet under controlled excitations.

A. K.M.F. Hussain, C. A. Thompson

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3 Scopus citations

Abstract

The organized motion in the near field of a plane turbulent jet under controlled excitation has been investigated by employing hot-wire techniques. Sinusoidal excitation is induced in the jet by a loud-speaker attached to the settling chamber and driven at the settling chamber cavity resonance fundamental frequency. The experiments were carried out at an exit pulsation amplitude of 1.4% of the exit velocity and cover a Strouhal number range 0.15-0.60 and a Reynolds number range 8,000-31,600. The effect of the excitation on the mean velocity is much smaller than that on the turbulent field. But unlike in a circular jet, the wave fundamental amplitude is a small fraction of the total rms turbulent velocity. The amplitude and phase distributions of the wave fundamental show that the disturbance which is induced as a symmetric mode remains symmetric at downstream stations. The wave fundamental reaches its maximum relative amplitude at the Strouhal number 0.18 at a streamwise distance of about 4 slit-widths downstream from the exit. The wave growth rate is much higher and the wave length much smaller in the shear layer than on the centerline of the jet. (A)

Original languageEnglish
Journal[No source information available]
StatePublished - 1975

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