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Investigation of Interactions Between Suction Chamber and Boundary Layer over Suction Walls Using Direct Numerical Simulations

von Soldenhoff, Richard and Lüdeke, Heinrich (2022) Investigation of Interactions Between Suction Chamber and Boundary Layer over Suction Walls Using Direct Numerical Simulations. ECCOMAS 2022, 2022-06-05 - 2022-06-09, Oslo, Norwegen.

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Abstract

For active boundary layer laminarization of commercial aircraft, appropriate suction surfaces have to be designed in order to reduce frictional drag. To investigate interactions between suction chamber, suction surface and boundary layer, Direct Numerical Simulations (DNS) of growing instabilities are carried out. The flow conditions are set according to wind tunnel tests conducted in the DNW-NWB subsonic wind tunnel in Braunschweig, Germany. The unsteady two-dimensional simulations cover a domain of the suction chamber, the porous surface with discrete slots in spanwise direction and the boundary layer. For these computations, the DLR flow solver FLOWer is used. It is a block structured code and used in its 4th order version. By the means of an initial condition, unstable Tollmien-Schlichting waves are introduced to the boundary layer flow and grow temporally during ongoing calculations. The growth rates of disturbances are evaluated in the boundary layer as well as in the suction chamber. In this way, the influences of slot dimensions such as the slot width and the suction sheet thickness are investigated. Beside qualitative observations of the effect, additional variations of the geometry allow quantification of the acoustic impedance for each slot geometry [1]. A direct correlation is found between the acoustic impedance and additional Tollmien-Schlichting wave growth in unstable boundary layers. This holds for all geometries and all investigated bondary layer profiles, including a natural boundary layer and two cases with suction. All evaluated impedance values and growth rates coincide on a single curve. These findings can be used as a basis for modifications of Linear Stability Theory methods for transition prediction of suction walls at given porous properties by implementing an impedance boundary condition at porous surfaces.

Item URL in elib:https://elib.dlr.de/191690/
Document Type:Conference or Workshop Item (Speech)
Additional Information:Im Rahmen des Exzellensclusters SE2A
Title:Investigation of Interactions Between Suction Chamber and Boundary Layer over Suction Walls Using Direct Numerical Simulations
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
von Soldenhoff, RichardUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lüdeke, HeinrichUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Date:2022
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Boundary Layer Suction, Hybrid Laminar Flow Control, Direct Numerical Simulations, Acoustic Impedance
Event Title:ECCOMAS 2022
Event Location:Oslo, Norwegen
Event Type:international Conference
Event Start Date:5 June 2022
Event End Date:9 June 2022
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 - Aircraft Technologies and Integration
Location: Braunschweig
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Transport Aircraft
Deposited By: von Soldenhoff, Richard
Deposited On:06 Dec 2022 11:56
Last Modified:24 Apr 2024 20:52

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