Physical space analysis of cross-scale turbulent kinetic energy transfer in premixed swirl flames

Understanding the cross-scale kinetic energy transport in turbulent flames is critical for physically-accurate modeling. This paper presents an experimental analysis of premixed swirl at Karlovitz numbers between 10 and 20 via physical space filtering. High-resolution tomographic particle image velocimetry formaldehyde planar laser induced fluorescence measurements are used to obtain 3D velocity fields, as well estimates progress variable density fields. Filtering these fields scales range laminar flame thickness (0.9<?/?L0<2.2) allows transfer across filter scale be quantified. Mean from sub-filter larger (i.e. back-scatter) occurs internal structure conditions studied, with maximum back-scatter occurring towards center flame. Compared equivalent non-reacting cases, considerably more occurred reacting flows all cases studied. At lower number, magnitude monotonically increased increasing scale. higher saturated around ?/?L0?1.8. A scaling proposed that quantifies relative significance swirl-induced pressure gradient flame-induced on pressure-work source energy, indicating swirling flow can significantly affect dynamics. Overall, results demonstrate combustion impacts configurations practical relevance. These conclusions have implications LES modelling strategies, providing evidence models should allow up-scale vicinity