RT Journal Article
ID 797d433a52942dc0
A1 Krasheninnikov, Sergei Yu. 
A1 Maslov, Vladimir Pavlovich
A1 Mironov, Aleksey Konstantinovich
A1 Toktaliev, Pavel Damirovich
T1 INVESTIGATION OF THE FLOW STRUCTURE AND ACOUSTIC FIELD OF A TURBULENT JET WITH HIGH SWIRLING INTENSITY
JF TsAGI Science Journal
JO TSAGI
YR 2016
FD 2016-10-20
VO 47
IS 2
SP 111
OP 137
K1 turbulent jet
K1 swirling jet
K1 turbulent jet noise
K1 sources of sound
K1 precession
K1 jet flow unsteadiness
AB The flow structure and acoustic field of free turbulent jets with high swirling intensity (<i>W</i><sub>0</sub>) are experimentally studied. Under these conditions, a recirculation flow exists in the paraxial region of the jet and a tonal sound is emitted. The averaged and nonstationary characteristics of the jet flow, precession motion, and velocity and pressure fluctuations are investigated. The study is based on using constant-temperature anemometry and particle image velocimetry with conditional phase averaging. Flows behind various swirling devices are analyzed. It is shown that the main properties of the averaged flow are determined by the intensity of flow swirling in the source (<i>W</i><sub>0</sub>). This fact allows the investigations to be limited by one source of the swirling jet. Unsteady flow in the jet and near the jet boundary is also simulated numerically. The results of the present investigations show that the jet flow structure is determined by the swirling intensity, which governs the configuration of the recirculation zone and precession of dynamic non-uniformities with respect to the jet axis. The precession frequency coincides with the first frequency of the discrete tone (<i>f</i><sub>0</sub>), which is adequately described by the general formula <i>Sh</i> &#61; <i>f</i><sub>0</sub><i>d</i> &#61; <i>u</i><sub>0</sub> &#61; 0.7<i>W</i><sub>0</sub> , where <i>d</i> is the exit diameter and <i>u</i><sub>0</sub> is the
averaged exhaustion velocity. The precession motion in the jet generates oscillations of air inflowing
to the jet with the same frequency <i>f</i><sub>0</sub>. The acoustic field is formed approximately at a distance of 5-10<i>d</i> from the jet boundary. The results of the present investigations suggest a relationship between jet noise generation and flow rate oscillations in the flow ejected by the jet.

PB Begell House
LK https://www.dl.begellhouse.com/journals/58618e1439159b1f,703c14f933ab4b97,797d433a52942dc0.html