Design and Tests of Wind-Tunnel Sidewalls for Receptivity Experiments on a Swept Wing

Romano, Diego; Alfredsson, P. Henrik; Hanifi, Ardeshir; Tillmark, Nils; Бородулин, В. И.; Ivanov, A. V.; Kachanov, Y. S.; Minervino, Mauro

doi:10.4028/www.scientific.net/amm.390.96

Cited by 8 publications

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“…In order to provide the spanwise base-flow uniformity (to meet the sweep condition inherent for infinite-span swept wings) the model was equipped with contoured sidewalls (see refs. [6][7][8] for more detail). Their shapes were calculated numerically and corresponded to satisfaction of the sweep condition for potential flow at the boundary-layer edge [6].…”

Section: Methodsmentioning

confidence: 99%

“…[6][7][8] for more detail). Their shapes were calculated numerically and corresponded to satisfaction of the sweep condition for potential flow at the boundary-layer edge [6]. General view on the model in the wind-tunnel test section is given in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…More detailed description of: (1) the experimental model, (2) the traversing systems, (3) the technique of peculiar spanwise positioning of the traverse 'Komarik' by means of a laser sheet, (4) the methods of measurements of shape oscillations of the surface source membranes, and other peculiarities of the receptivity experiments can be found in refs. [6][7][8].…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Generation of unsteady CF-instability modes by vibrational and vibration-vortex localized receptivity mechanisms

Kachanov¹,

Бородулин²,

Ivanov³

et al. 2018

AIP Conference Proceedings

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The paper is based on results obtained within an international project 'RECEPT' of the European Framework Program FP7. The experiments were carried out in a three-dimensional boundary layer developing on an experimental model of a long-laminar-run swept airfoil (sweep angle of 35°). The model was mounted in a test section of the lowturbulence wind-tunnel MTL (KTH, Stockholm) at an angle of attack of −5° and equipped with sidewalls provided satisfaction of infinite-span conditions. The cross-flow (CF) instability modes were predominant in this case, while the Tollmien-Schlichting (TS) waves were suppressed by a favorable pressure gradient. The main measurements were carried out by means of hot-wire anemometry at conditions of excitation of fully controlled, unsteady surface and flow perturbations. These perturbations were excited by special sources: (1) a row of oscillating membranes and (2) a vibrating wire, at frequencies of fs and fv, respectively. A very good, quantitative agreement between the measured and calculated (by linear stability theory based on PSE approach) amplification curves was found at surface frequency fs. However, the evolution of the CF-modes excited at difference combination frequency fsv-= fs-fv turned out to be very much different from the theoretical one. Thorough analysis of the obtained results has shown that the only explanation of these discrepancies can be associated with presence of a distributed receptivity mechanism due to scattering of freestream vortices on the CF-instability waves excited by surface vibrations. Another unusual and unexpected phenomenon found in the present experiments is associated with anomalous amplification of difference combination modes with the zero spanwise wavenumbers ′. This phenomenon was observed in the flow, which is stable with respect to both CF-and TSwaves having ′ = 0 for all frequencies. There is no explanation of this finding at present.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Generation of unsteady CF-instability modes by vibrational and vibration-vortex localized receptivity mechanisms

Kachanov¹,

Бородулин²,

Ivanov³

et al. 2018

AIP Conference Proceedings

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“…Both design of the experimental setup and planning of the measurement campaign were based on prior CFD calculations. The details concerning a shape of the mentioned above contoured wall bumps may be found in [5,6]. The preliminary analysis of stability curves provided us with the suitable location of the built-in disturbance source and the ranges of frequencies and wavenumbers to be studied.…”

Section: Preparatory Calculationsmentioning

confidence: 99%

Excitation of 3D TS-waves in a swept-wing boundary layer by surface vibrations and freestream vortices

Бородулин

Ivanov

Kachanov

et al. 2018

AIP Conference Proceedings

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There are several kinds of velocity disturbances, which may affect the transition to turbulence in a swept wing boundary layer. Tollmien-Schlichting (TS) waves are among most important of them. The properties of TS waves and their potential competition with cross-flow waves on a swept wing are poorly studied in theoretical works and were not studied experimentally at all. This paper presents the method of excitation of fully controlled 3D TS waves via interaction of freestream vortices and surface vibrations. The experimental approach developed here will be used for investigation of the corresponding receptivity problem.

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“…The experiments were carried out in the Minimum Turbulence Level (MTL) wind tunnel at KTH (Stockholm) in a 3D boundary layer of a high-precision experimental model. It represents a long-laminar-run airfoil section of a swept wing with chord length normal to the leading edge of 800 mm and sweep angle of 35 degrees equipped with sidewalls of special shape mounted at the ceiling and the floor of the test section [11]. The sidewalls served for satisfaction of the infinite-span swept-wing conditions (see Fig.…”

Section: Methodsmentioning

confidence: 99%

Receptivity coefficients of vortex-vibrational type at excitation of 3D Tollmien-Schlichting waves in a boundary layer on a swept wing

Бородулин

Ivanov

Kachanov

et al. 2019

HIGH-ENERGY PROCESSES IN CONDENSED MATTER (HEPCM 2019): Proceedings of the XXVI Conference on High-Energy Processes in Condense

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The paper is devoted to the first results of an experimental quantitative study of the receptivity mechanism of a swept-wing laminar boundary layer related to scattering of 2D freestream vortices (with frequency f v) at 3D local surface vibrations (with frequency f s) resulting in an excitation of Tollmien-Schlichting (TS) waves (having combination frequencies f + = f s + f v and f-= f s-f v). The experiments were carried out in a low-turbulence level wind tunnel on a highprecision experimental model of long-laminar-run swept airfoil (sweep angle of 35°) at a freestream speed of about 10 m/s. Controlled localized 3D surface vibrations and 2D freestream vortices were generated by special disturbance sources. Quantitative characteristics of the studied receptivity mechanism (receptivity coefficients) were estimated.

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Design and Tests of Wind-Tunnel Sidewalls for Receptivity Experiments on a Swept Wing

Cited by 8 publications

References 0 publications

Generation of unsteady CF-instability modes by vibrational and vibration-vortex localized receptivity mechanisms

Generation of unsteady CF-instability modes by vibrational and vibration-vortex localized receptivity mechanisms

Excitation of 3D TS-waves in a swept-wing boundary layer by surface vibrations and freestream vortices

Receptivity coefficients of vortex-vibrational type at excitation of 3D Tollmien-Schlichting waves in a boundary layer on a swept wing

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