Analysis of simultaneous measurement of acoustic pressure in the far-field and density gradient in the near-field in a cold jet
2013 (English)In: 19th AIAA/CEAS Aeroacoustics Conference, 2013Conference paper (Refereed)
The purpose of the investigation presented here is to study the degree of correlation between the density gradient in the near field and the aeroacoustic sound generation in the far field of a cold jet. The variations of the density gradient in the flow are visualized and recorded by the Background Oriented Schlieren (BOS) technique. In this method high power LEDs are used as illumination source. Simultaneously the pressure fluctuations in the acoustic far-field are recorded by a set of microphones. Measurements on a round nozzle and a chevron nozzle are conducted and the obtained results are compared. Large structures emitting noise are localized, being in the case of the chevron nozzle further upstream due to the higher level of entrainment of the jet with the surrounded ambient fluid. In addition, it is demonstrated that the noise produced by these structures is radiated mainly downstream, having the highest correlations with the pressure fluctuations recorded with the microphone located at an angle θ = 26° respect to the jet-axis.
Place, publisher, year, edition, pages
Acoustic pressures, Aeroacoustic sound, Background oriented schlieren, Degree of correlations, Density gradients, Illumination sources, Pressure fluctuation, Simultaneous measurement
IdentifiersURN: urn:nbn:se:kth:diva-133292DOI: 10.2514/6.2013-2034ScopusID: 2-s2.0-84883707228ISBN: 978-162410213-4OAI: oai:DiVA.org:kth-133292DiVA: diva2:660311
19th AIAA/CEAS Aeroacoustics Conference; Berlin; Germany; 27 May 2013 through 29 May 2013
QC 201310292013-10-292013-10-292013-10-29Bibliographically approved