scholarly journals Validation of a laminar-turbulent transition prediction technique for a swept-wing boundary-layer flow

2021 ◽  
Vol 2057 (1) ◽  
pp. 012081
Author(s):  
A V Boiko ◽  
V I Borodulin ◽  
A V Ivanov ◽  
S V Kirilovskiy ◽  
D A Mischenko ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Test Section ◽  
Wind Tunnel Test ◽  
Cross Flow ◽  
Infrared Camera ◽  
Main Flow ◽  
Swept Wing ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

Abstract The laminar-turbulent transition in the boundary layer of a 45° swept wing model installed at zero attack angle in the test section of a subsonic wind-tunnel was detected with the help of an infrared camera. The camera recorded sequences of frames, the evolution of the preheated model surface temperature acquired and used for differentiating between the laminar and turbulent regions. The transition onset was evaluated at both sides of the model. Corresponding main flow computations in the virtual wind tunnel test section were performed at the same flow conditions with ANSYS Fluent. The computed main-flow velocity profiles along inviscid streamlines were used for analysis of hydrodynamic stability of the boundary layer with respect to Tollmien-Schlichting waves and stationary cross-flow vortices to obtain N-factor distributions along the model chord. A comparison of the experimental and the computed transition onsets was performed.

The Effect of the Source Location on the Acoustic Excitation on Laminar-Turbulent Transition on Swept Wing Boundary Layer

2002 ◽  
Author(s):  
B. Gu¨lac¸ti ◽  
S. Aubrun ◽  
A. Seraudie ◽  
D. Arnal
Keyword(s):  
Wind Tunnel ◽  
Test Section ◽  
Three Dimensional ◽  
Source Location ◽  
Sound Level ◽  
Acoustic Excitation ◽  
Hot Wire ◽  
Swept Wing ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

The effect of the source location and the direction of the propagation on the laminar-turbulent transition on swept-wing three-dimensional boundary layers are investigated experimentally. Also the crossflow case is handled in detail. The source for the acoustic excitation is placed in four different locations: in front of the wing, on top of the test section, behind the wing and in front of the wind tunnel. Three different experimental cases (streamwise, crossflow and mixed cases) are examined for each location with two different excitation bands. For the most efficient frequency ranges and the highest sound pressure levels an upstream shift of transition motion between 20%–35% of chord length for streamwise case and between 5%–10% for the crossflow case are observed. While in front of the wing and behind the wing are the most efficient loudspeaker positions in the streamwise case, in the crossflow case the most efficient locations are observed to be in front of the wing and on top of the test section. It is concluded that acoustic sound level plays a more important role in the upstream shift of the transition than the source location and placing the loudspeaker in front of the wind tunnel is not an efficient position. For the crossflow instabilities dominated transition the stationary vortices are clearly seen from the velocity contours obtained by the hot-wire. Secondary instabilities couldn’t be observed in the hot-wire spectra. The surface roughness of the wing that is reduced to 0.25µm does not change the transition location in the crossflow case.

Control of a swept-wing boundary layer using ring-type plasma actuators

2018 ◽  
Vol 844 ◽  
pp. 36-60 ◽  
Author(s):  
Nima Shahriari ◽  
Matthias R. Kollert ◽  
Ardeshir Hanifi
Keyword(s):  
Boundary Layer ◽  
Cross Flow ◽  
Plasma Actuators ◽  
Swept Wing ◽  
Ring Type ◽  
Transition Control ◽  
Turbulent Transition ◽  
Roughness Elements ◽  
Order Of Magnitude ◽  
Induced Velocity

Application of ring-type plasma actuators for control of laminar–turbulent transition in a swept-wing boundary layer is investigated thorough direct numerical simulations. These actuators induce a wall-normal jet in the boundary layer and can act as virtual roughness elements. The flow configuration resembles experiments by Kim et al. (2016 Technical Report. BUTERFLI Project TR D3.19, http://eprints.nottingham.ac.uk/id/eprint/46529). The actuators are modelled by the volume forces computed from the experimentally measured induced velocity field at the quiescent air condition. Stationary and travelling cross-flow vortices are triggered in the simulations by means of surface roughness and random unsteady perturbations. Interaction of vortices generated by actuators with these perturbations is investigated in detail. It is found that, for successful transition control, the power of the actuators should be increased to generate jet velocities that are one order of magnitude higher than those used in the experiments by Kim et al. (2016) mentioned above.

scholarly journals Large-eddy simulation of laminar-turbulent transition in a swept-wing boundary layer

1997 ◽  
Author(s):  
Xiaoli Huai ◽  
Ugo Piomelli ◽  
Ronald Joslin ◽  
Xiaoli Huai ◽  
Ugo Piomelli ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Swept Wing ◽  
Eddy Simulation ◽  
Turbulent Transition ◽  
Large Eddy ◽  
Laminar Turbulent Transition

scholarly journals The effect of small angle of attack on the laminar-turbulent transition in boundary layer on swept wing at Mach number M=2

2017 ◽  
Author(s):  
N. V. Semionov ◽  
Yu. G. Yermolaev ◽  
A. D. Kosinov ◽  
A. N. Semenov ◽  
B. V. Smorodsky ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Small Angle ◽  
Angle Of Attack ◽  
Swept Wing ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

scholarly journals Experimental Study of the Influence of Unit Reynolds Number on the Laminar-Turbulent Transition on the Model Swept Wing with a Subsonic Leading Edge at M = 2

2021 ◽  
Vol 16 (1) ◽  
pp. 44-52
Author(s):  
Vasilii L. Kocharin ◽  
Nikolai V. Semionov ◽  
Alexander D. Kosinov ◽  
Aleksey A. Yatskikh ◽  
Sofia A. Shipul ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Experimental Studies ◽  
Leading Edge ◽  
Supersonic Boundary Layer ◽  
Swept Wing ◽  
Unit Reynolds Number ◽  
Flow Parameters ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

Experimental studies of the influence of unit Reynolds number on the laminar-turbulent transition in a supersonic boundary layer of a swept wing with a subsonic leading edge at Mach number 2 are performed. The experiments were performed on a model of a swept wing with a swept angle of the leading edge of 72 degrees and with a 3% profile with a variable chord length in span. The hot-wire measurements showed that a laminar-turbulent transition in a supersonic boundary layer of a swept wing with a subsonic leading edge occurs earlier (~25-30%) than on a model with a supersonic leading edge with the same oncoming flow parameters. It is shown that a change unit Reynolds number insignificant influence the laminar-turbulent transition in the boundary layer of a swept wing with a subsonic leading edge.

Simulation of the laminar-turbulent transition in the boundary layer of the swept wing in the subsonic flow at angles of attack

2020 ◽  
Author(s):  
S. V. Kirilovskiy ◽  
A. V. Boiko ◽  
K. V. Demyanko ◽  
Y. M. Nechepurenko ◽  
T. V. Poplavskaya
Keyword(s):  
Boundary Layer ◽  
Subsonic Flow ◽  
Swept Wing ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

Experimental study of laminar-turbulent transition on a swept wing with local boundary-layer suction at subsonic velocities

1998 ◽  
Vol 33 (4) ◽  
pp. 519-525
Author(s):  
V. F. Babuev ◽  
V. I. Biryukov ◽  
V. D. Bokser ◽  
A. F. Kiselev ◽  
V. G. Mikeladze ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Swept Wing ◽  
Local Boundary ◽  
Boundary Layer Suction ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition
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