Spectra of turbulent energy transport in channel flows

etc15 Tracking Number 266

To reveal the scale-dependences of the transport of turbulent energy in a channel flow, the constituents of the budget equation of turbulent energy for the Fourier modes of velocity fluctuations are computed by using direct numerical simulations. At each height in the buffer and overlap regions, the transport in the wall-normal direction by the turbulent convection provides energy to the fluctuations at small scales, but takes it away from those at large-scales. Furthermore, energy taken from the large-scales in the overlap region is carried upward to the center of channel and also downward to the vicinity of the wall. This downward transport is expected to cause the anomaly of the turbulent intensity and the constituents of the budget equation near the wall. The transport between scales and their scaling will also be discussed in the talk.