Numerical Investigation of Cross-Flow Instability for a Supersonic Swept Wing with a Biconvex Airfoil

2022 ◽  
Author(s):  
Anthony P. Haas ◽  
Christoph Hader ◽  
Hermann F. Fasel
Keyword(s):  
Numerical Investigation ◽  
Flow Instability ◽  
Cross Flow ◽  
Swept Wing

Receptivity and sensitivity of the leading-edge boundary layer of a swept wing

2015 ◽  
Vol 775 ◽  
Author(s):  
Gianluca Meneghello ◽  
Peter J. Schmid ◽  
Patrick Huerre
Keyword(s):  
Boundary Layer ◽  
Flow Instability ◽  
Cross Flow ◽  
Leading Edge ◽  
Open Loop ◽  
Base Flow ◽  
Local Instability ◽  
Swept Wing ◽  
Global Mode ◽  
Attachment Line

A global stability analysis of the boundary layer in the leading edge of a swept wing is performed in the incompressible flow regime. It is demonstrated that the global eigenfunctions display the features characterizing the local instability of the attachment line, as in swept Hiemenz flow, and those of local cross-flow instabilities further downstream along the wing. A continuous connection along the chordwise direction is established between the two local eigenfunctions. An adjoint-based receptivity analysis reveals that the global eigenfunction is most responsive to forcing applied in the immediate vicinity of the attachment line. Furthermore, a sensitivity analysis identifies the wavemaker at a location that is also very close to the attachment line where the corresponding local instability analysis holds: the local cross-flow instability further along the wing is merely fed by its attachment-line counterpart. As a consequence, global mode calculations for the entire leading-edge region only need to include attachment-line structures. The result additionally implies that effective open-loop control strategies should focus on base-flow modifications in the region where the local attachment-line instability prevails.

Free-stream turbulence and the development of cross-flow disturbances

2013 ◽  
Vol 735 ◽  
pp. 347-380 ◽  
Author(s):  
Robert S. Downs ◽  
Edward B. White
Keyword(s):  
Surface Roughness ◽  
Flow Problem ◽  
Free Stream ◽  
Flow Instability ◽  
Cross Flow ◽  
Stream Velocity ◽  
Swept Wing ◽  
Free Stream Turbulence ◽  
Flow Disturbances ◽  
The Cross

AbstractThe cross-flow instability that arises in swept-wing boundary layers has resisted attempts to describe the path from disturbance initiation to transition. Following concerted research efforts, surface roughness and free-stream turbulence have been identified as the leading providers of initial disturbances for cross-flow instability growth. Although a significant body of work examines the role of free-stream turbulence in the cross-flow problem, the data more relevant to the flight environment (turbulence intensities less than 0.07 %) are sparse. A series of recent experiments indicates that variations within this range may affect the initiation or growth of cross-flow instability amplitudes, hindering comparison among results obtained in different disturbance environments. To address this problem, a series of wind tunnel experiments is performed in which the free-stream turbulence intensity is varied between 0.02 % and 0.2 % of free-stream velocity,${U}_{\infty } $. Measurements of the stationary and travelling mode amplitudes are made in the boundary layer of a 1.83 m chord,$45{{}^\circ} $swept-wing model. These results are compared to those of similar experiments at higher turbulence levels to broaden the current knowledge of this portion of the cross-flow problem. It is observed that both free-stream turbulence and surface roughness contribute to the initiation of unsteady disturbances, and that free-stream turbulence affects the development of both stationary and unsteady cross-flow disturbances. For the range tested, enhanced free-stream turbulence advances the transition location except when a subcritically spaced roughness array is employed.

scholarly journals Quantitative study of localized mechanisms of excitation of cross-flow instability modes in a swept-wing boundary layer

2018 ◽  
Vol 1129 ◽  
pp. 012008
Author(s):  
V I Borodulin ◽  
A V Ivanov ◽  
Y S Kachanov ◽  
D A Mischenko ◽  
R Örlü ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Quantitative Study ◽  
Flow Instability ◽  
Cross Flow ◽  
Swept Wing ◽  
Instability Modes

The Investigation of Stages of Cross Flow Instability Developing on the Leading Edge of the Swept Wing by Liquid-Crystal Thermography Method

2012 ◽  
Vol 7 (2) ◽  
pp. 80-84
Author(s):  
Stepan Tolkachev ◽  
Vasily Gorev ◽  
Viktor Kozlov
Keyword(s):  
Liquid Crystal ◽  
Flow Instability ◽  
Roughness Element ◽  
Cross Flow ◽  
Leading Edge ◽  
Swept Wing ◽  
Liquid Crystal Thermography ◽  
Element Size ◽  
Speed Range ◽  
Stationary Behavior

The liquid crystal thermography technique was tested for the investigation of stages of stationary disturbance developing after the roughness element and for indication of turbulence on the swept wing leading edge. It was shown, that stationary disturbance is easy to excite by the roughness element, develops along the streamline. The stationary behavior dependence from the roughness element size was investigated. It was determined, that the turbulence doesn’t develop along the leading edge in the explored speed range

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