Aeroacoustic near-field measurements with microscale resolution

作者：Haufe D^*; Pietzonka S; Schulz A; Bake F; Enghardt L; Czarske J W; Fischer A

来源：Measurement Science and Technology, 2014, 25(10): 105301.

DOI：10.1088/0957-0233/25/10/105301

• aeroacoustics
• microscale measurement
• bias flow liner
• laser Doppler velocity profile sensor

In order to analyse aeroacoustic phenomena at near-fields, e.g. the sound-flow interaction at aircraft engine liners, measurements of the flow velocity and the acoustic particle velocity (APV) with microscale resolution are required. To this end, the APV measurement with a high spatial resolution of 10 mu m was conducted by means of a laser Doppler velocity profile sensor. For validation of the APV measurements using the profile sensor in a superposed flow, a good agreement with indirect microphone measurements as a reference was achieved, up to a maximum Mach number of 0.25. Aeroacoustic measurements at a minimum distance of 350 mu m to the perforation of a bias flow liner were performed using the profile sensor. As a result, acoustically induced velocity oscillations near the rim of the orifice were detected with microscale resolution. The phase-resolved oscillation field indicates vortex shedding from the perforation, which is initiated by the sound-flow interaction. Thus, it is demonstrated that the profile sensor is a valuable tool for analysing aeroacoustic phenomena at near-fields, down to the Kolmogorov scale.

• 出版日期2014-10