Reflected shock tube experiments on aeroacoustic signature of hot jets

Experimental Investigation on Acoustic Wave Generation due to Supersonic Hot Jet Impingement on an Inclined Flat Plate

“…1) are provided by a reflected shock wave. Different shock and reflected shock strengths are generated through proper helium/air mass fractions at different pressures and temperatures while the driven section is vacuumed to the designed pressure (Jahromi et al;2017).…”

“…The initial driven pressure (P1) is specified so that when the designed initial and reflected shock waves passes over the driven gas, the designed pressure at nozzle reservoir (P5) for an ideally expanded jet at M = 1.4 is gained. The length of driver and driven section, the diameter of the shock tube pipe, and the helium/air mass fraction are tailored to have the maximum test time (Jahromi et al, 2017). The test time of quasi-steady pressure and temperature at nozzle reservoir is limited by the arrival of the reflected expansion waves from the end of driver section and is 11 ms in the present study.…”

“…(8) to (11) and the uncertainties in sensor calibration charts, the uncertainty in the pressure and temperature measurement at the nozzle inlet is kept below 0.5% and an uncertainty in acoustic measurement with less than 0.5 db is assured. For additional information on the shock tube facility, instrumentation, test procedure, and validation of acoustic results, the reader is referred to a previous paper by the authors (Jahromi et al, 2017).…”

“…In the case of hot free jets, two distinct types of acoustic waves are observed at the far-field: a peaky, high-amplitude acoustic wave at 30° ≤ θ ≤ 45° and a flat frequency-spectrum with low-amplitude acoustic wave at 75° ≤ θ ≤ 90° (Tam, 1991;Tam, 1996;Hileman et al, 2005;Casalino et al, 2008;Koenig et al, 2013;Jahromi et al, 2017;Balakrishnan et al, 2018).…”

“…The required jet is generated by a reflected shock tube with a relatively very low jet noise development (Oertel, 1979;Kirk et al, 2001;Sen et al, 2013;Jahromi et al, 2017). A brief review of the test facility is given in section 2.…”