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Investigation of Shock Boundary Layer Interactions in the Transonic Buffet flow of a Compressor Cascade using High-Speed PIV and Shadowgraphs

Klinner, Joachim and Hergt, Alexander Silvio and Grund, Sebastian and Willert, Christian (2021) Investigation of Shock Boundary Layer Interactions in the Transonic Buffet flow of a Compressor Cascade using High-Speed PIV and Shadowgraphs. Near-Wall Flow in Turbomachinery Blade Rows, 28.-29. Jan. 2021, virtuell.

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Official URL: https://tu-dresden.de/ing/maschinenwesen/ism/tfa/workshop/

Abstract

The dynamics of a transonic buffet flow on the suction side of a highly loaded 2-D compressor blade model is investigated in a cascade indtunnel at a chord based Reynolds number of 1.4x106 and an 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/U1=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. 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 [Lee1990] which describes self-sustained shock-buffet as a consequence of shock - trailing edge interactions.

Item URL in elib:https://elib.dlr.de/142144/
Document Type:Conference or Workshop Item (Speech)
Title:Investigation of Shock Boundary Layer Interactions in the Transonic Buffet flow of a Compressor Cascade using High-Speed PIV and Shadowgraphs
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Klinner, JoachimJoachim.Klinner (at) dlr.dehttps://orcid.org/0000-0003-2709-9664
Hergt, Alexander SilvioAlexander.Hergt (at) dlr.deUNSPECIFIED
Grund, Sebastiansebastian.grund (at) dlr.deUNSPECIFIED
Willert, ChristianChris.Willert (at) dlr.dehttps://orcid.org/0000-0002-1668-0181
Date:28 January 2021
Refereed publication:No
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Series Name:DFG PAK 948
Status:Published
Keywords:High-speed PIV, transonic flows, shock - boundary layer interaction, SBLI, buffet flow, turbomachinery flow
Event Title:Near-Wall Flow in Turbomachinery Blade Rows
Event Location:virtuell
Event Type:Workshop
Event Dates:28.-29. Jan. 2021
Organizer:TU-Dresden
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: Klinner, Dr.-Ing. Joachim
Deposited On:09 Jun 2021 09:27
Last Modified:09 Jun 2021 09:27

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