The cross-scale flux of turbulent kinetic energy by baropycnal work in bluff body stabilized flames

Baropycnal work is a localized cross-scale transfer of turbulence kinetic energy (i.e., energy cascade) due to both barotropic and baroclinic density gradients, and is implicitly contained within the standard Favre-filtered representation of the pressure-gradient velocity correlation in the variable-density large eddy simulation (LES) framework. In shock waves and non-reacting compressible isotropic turbulence, the baropycnal work acts counter to the well-known advective energy cascade, backscattering energy from small to large scales on average. In the present study, the cross-scale flux of turbulence kinetic energy by baropycnal work is examined in bluff body stabilized flames with and without background pressure gradients using data from direct numerical simulations. The relative strength and direction (i.e. down- or up-scale) of the baropycnal flux will be directly compared to both the advective inter-scale flux and the pressure-dilation work, which acts to directly convert heat released by the flame into turbulence kinetic energy without a cross-scale flux.