Uniform flow injection into a turbulent boundary layer for trailing edge noise reduction

Máté Szőke*, Daniele Fiscaletti, Mahdi Azarpeyvand

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

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Abstract

The hydrodynamic effects of inclined uniform continuous blowing on a turbulent boundary layer are investigated experimentally. A laminar flow is introduced into the boundary layer through a fence on a flat plate at a distance of 3.38δ0 upstream of the trailing edge. The effects of this open-loop technique of flow control are examined at different angles of injection and at different blowing rates. Surface pressure fluctuations acquired from flush-mounted microphones are used to estimate the trailing edge noise. Injection angles of 70° and 90° in combination with strong blowing rates enable a noise reduction of up to 15 dB at mid and high frequencies, f > 300 Hz. Similar aeroacoustic performances are obtained at a blowing angle of 50° but at lower blowing rates. At low frequencies, a penalty is expected, with the trailing edge noise increasing for all the injection angles and blowing rates under analysis. Mean velocity profiles from hot-wire anemometry reveal that high injection angles and strong blowing rates induce a flow separation, which is expected to deteriorate the aerodynamic performances. When applying a uniform blowing at 50°, however, no flow separation occurs. From an aeroacoustic and aerodynamic point of view, uniform blowing applied at 50° and at intermediate blowing rates is found to be the most promising setting.
Original languageEnglish
Article number 085104 (2020)
Number of pages15
JournalPhysics of Fluids
Volume32
Early online date10 Aug 2020
DOIs
Publication statusE-pub ahead of print - 10 Aug 2020

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