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High-Speed PIV of shock boundary layer interactions in the transonic buffet flow of a compressor cascade

Klinner, Joachim and Hergt, Alexander Silvio and Grund, Sebastian and Willert, Christian (2021) High-Speed PIV of shock boundary layer interactions in the transonic buffet flow of a compressor cascade. Experiments in Fluids, 62, p. 58. Springer Nature. doi: 10.1007/s00348-021-03145-3. ISSN 0723-4864.

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Official URL: https://link.springer.com/article/10.1007/s00348-021-03145-3


The dynamics of a transonic buffet flow on the suction side of a highly loaded 2-D compressor blade model is investigated at a chord based Reynolds number of 1.4x10^6 and a inlet Mach number of 1.05. Near stall the detached bow shock exhibits pronounced modal shock oscillations at buffet frequencies of w*=2\pi f c / U_1=2.27 which are not related to any structural aeroelastic modes. High-speed PIV at several stations along the chord provides chordwise velocity spectra and wave propagation velocities of shock-induced perturbations. For this purpose, a double-pulse laser system with a high-repetition rate was set up consisting of two combined DPSS lasers. This enables time-resolved PIV using frame straddling at up to 100 kfps and pulse separations down to 800 ns. Synchronized high-speed shadowgraph imaging simultaneously locates the position of the bow shock. Based on cross-correlations between velocity time records at two points and between velocity and shock position, the propagation velocity of the modal perturbations is determined upstream and downstream from the shock. The measured data indicates that feedback occurs between a region immediately downstream of the shock foot and a plane upstream of the shock, up to which transverse velocity disturbances are convected. This observation is contrary to Lee's model (AIAA J 28(5):942-944, 1990) which describes self-sustained shock-buffet as a consequence of shock - trailing edge interactions.

Item URL in elib:https://elib.dlr.de/141223/
Document Type:Article
Title:High-Speed PIV of shock boundary layer interactions in the transonic buffet flow of a compressor cascade
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Klinner, JoachimUNSPECIFIEDhttps://orcid.org/0000-0003-2709-9664UNSPECIFIED
Hergt, Alexander SilvioUNSPECIFIEDhttps://orcid.org/0009-0008-1643-7326UNSPECIFIED
Willert, ChristianUNSPECIFIEDhttps://orcid.org/0000-0002-1668-0181UNSPECIFIED
Date:1 March 2021
Journal or Publication Title:Experiments in Fluids
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:p. 58
Publisher:Springer Nature
Keywords:transonic compressor, buffet flow, boundary-layer-shock interaction, high-speed imaging, particle image velocimetry, PIV
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Efficient Vehicle
DLR - Research area:Aeronautics
DLR - Program:L EV - Efficient Vehicle
DLR - Research theme (Project):L - Virtual Aircraft and  Validation
Location: Köln-Porz
Institutes and Institutions:Institute of Propulsion Technology > Engine Measurement Systems
Institute of Propulsion Technology > Fan and Compressor
Deposited By: Willert, Dr.phil. Christian
Deposited On:22 Mar 2021 07:18
Last Modified:12 May 2023 13:06

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