3D reconstruction of a compressible flow by synchronized multi-camera BOS

Autor: Olivier Léon, François Nicolas, G. Le Besnerais, Frédéric Champagnat, David Donjat, F. Micheli
Přispěvatelé: ONERA - The French Aerospace Lab [Toulouse], ONERA, ONERA - The French Aerospace Lab [Palaiseau], ONERA-Université Paris Saclay (COmUE)
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Experiments in Fluids
Experiments in Fluids, Springer Verlag (Germany), 2017, 58 (5), ⟨10.1007/s00348-017-2325-y⟩
ISSN: 0723-4864
1432-1114
Popis: International audience; This paper investigates the application of the 3D density reconstruction from a limited number of Background Oriented Schlieren (BOS) images, recently proposed in Nicolas et al (2016), to the case of compressible flows such as underexpanded jets. First, an optimization of a 2D BOS setup is conducted in order to mitigate the intense local blurs observed in raw BOS images and caused by strong density gradients present in the jets. It is demonstrated that a careful choice of experimental conditions enables one to obtain sharp deviation fields from 2D BOS images. Second, a 3DBOS experimental bench involving 12 synchronized cameras is specifically designed for the present study. It is shown that the 3DBOS method is able to provide physically consistent 3D reconstructions of instantaneous and mean density fields for various underexpanded jet flows issued into quiescent air. Finally, an analysis of the jet density structure is conducted for a moderately underexpanded jet through phase-averaging, highlighting the development of a largescale coherent turbulent structure associated with a jet shear layer instability.
Databáze: OpenAIRE
Externí odkaz: