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Evaluation of Interferograms of Unsteady Subsonic Airflow Past a Fluttering Airfoil
Šidlof, P. ; Riss, Š. ; Vlček, Václav
The paper reports on time-resolved interferometric measurements of unsteady ow elds around a uttering NACA0015 airfoil. A mechanical model with two degrees of freedom (pitch and plunge) has been designed and tested in a high-speed subsonic wind tunnel. Aeroelastic instability of the classical utter and dynamic stall type has been observed in the Mach number range M = 0.2 - 0.5. The interferograms were recorded using a Mach-Zehnder interferometer and a high-speed camera. An in-house software IFGPro was developed for the postprocessing and evaluation of the interferogram sequences, yielding pressure distribution, lift and drag force on the airfoil.
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Modelling of the Laminar/Turbulenttransition on a Heated Flat Plate Using the k-kL-w Model
Kožíšek, Martin ; Fürst, J. ; Příhoda, Jaromír
The contribution deals with the numerical simulation of the transition to turbulence on a heated flat plate by means of the k-kL-k-kL-w model of Walters and Cokljat (2008). The revised version of the three-equation model was implemented into the OpenFOAM code for the incompressible and compressible flows. Numerical simulations of the boundary-layer development were carried out according to measurements of Sohn and Reshotko (1991). The transition model was tested by means of the skin friction and the Stanton number distributions for various free-stream turbulence levels. Results were compared with empirical correlations expressing the Reynolds analogy according to Kays and Crawford (1993) and with experimental data of Pinson and Wang (2000).
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