Reconstruction of turbulent flow from temperature field measured using Background Oriented Schlieren

• Published in: International Journal of Thermofluids 2024-08, Vol.23, p.100744, Article 100744
• Main Authors: Rudenko, Yulia K., Vinnichenko, Nikolay A., Pushtaev, Aleksei V., Plaksina, Yulia Yu, Uvarov, Alexander V.
• Format: Article
• Language: English
• Subjects: Background Oriented Schlieren; Data assimilation; Seedless velocimetry; Turbulent jet
• ISSN: 2666-2027; 2666-2027
• DOI: 10.1016/j.ijft.2024.100744

New data assimilation technique for turbulent flows is proposed, which allows determination of the turbulent viscosity, velocity and pressure distributions from the experimentally measured temperature fields. Measurements are performed for a round jet of hot air using nonintrusive Background Oriented Schlieren technique. Thus, seedless velocity and pressure measurement is realized, as well as measurement of the turbulent viscosity field without usage of any particular turbulence model. Data assimilation results are shown to be in good agreement with the conventional RANS simulations using the Spalart–Allmaras and k-ɛ turbulence models, if adequate smoothing of the input temperature field is performed and sufficient regularization of the energy equation in regions with uniform temperature is provided. [Display omitted] •Velocity and eddy viscosity are determined from the measured temperature fields.•Turbulence model equations are not used in data assimilation.•Mean flow is reconstructed for a turbulent jet of hot air from a circular nozzle.•The input temperature fields are measured using Background Oriented Schlieren.•Accurate velocity fields are obtained without seeding.