Linear-model-based study of the coupling between velocity and temperature fields in compressible turbulent channel flows

It is generally believed that the temperature and velocity fields are highly coupled in compressible wall-bounded turbulence. In present study, we employ a linear model, i.e. two-dimensional spectral stochastic estimation (SLSE), to study this coupling from perspective of multi-scale energy-containing eddies. Particular attention paid relevant statistical characteristics field. The connections two found be varied with wall-normal position boundary layer. nutshell, their entanglement strongest near-wall region, only extreme thermal events cannot captured by SLSE. logarithmic scales correspond attached eddies very large-scale motions (VLSMs) firmly coupled. footprints former organized an additive manner fulfil predictions celebrated attached-eddy model. outer linearly at corresponding VLSMs. These findings demonstrated insensitive Mach number effects ascribed similarity between momentum heat transfer wall also shown it Reynolds rather than acts as key parameter constructing coupling. framework built may pave way for investigating multi-physics turbulence, reinforcing our analysing modelling capability interrelated problems.