Multi-scale energy transfer in near-wall region of turbulent channel flow

The multi-scale energy transfer in near-wall turbulence is studied byorthonormal wavelets and the database of channel turbulence obtained bydirect numerical simulation. By a multi-scale decomposition of the flow fieldin streamwise and spanwise directions, the difference of energy transferbetween these two directions is investigated. It is found that the energy transferin the streamwise direction is dominated by back scatter, while in thespanwise direction, there is an obvious forward transfer, which is notconfined in the viscous sublayer only like that in the streamwise direction.With a lager filter width, the forward energy transfer in the spanwise directionbecomes dominant.