Skip to content Skip to navigation

Attached eddies in turbulent channel flow: scale interactions and spectral energy transfer

Event Type: 
Date and Time: 
Friday, January 12, 2018 - 16:30
CTR Conference Room 103
Event Sponsor: 
Parviz Moin, Director of Center for Turbulence Research
Dr. Minjeong Cho

A large-eddy simulation of turbulent channel flow at Re_tau=1700 is conducted to clarify scale interactions and spectral energy transfer. The spectral turbulent kinetic energy equation is considered with emphasis on the visualization of triadic interactions in turbulent energy transport between the Fourier modes. The major role of the turbulent transport is turned out to be the energy cascade, as in many other turbulent shear flows. In addition to this, two new types of scale interaction processes have been discovered in the near-wall region. First, for relatively small energy-containing motions, part of the energy transfer mechanisms in the energy cascade is provided by interactions between larger energy-containing motions. Second, there exists an energy transfer from small to large scales, and this is particularly important for the streamwise and spanwise velocity components in the near-wall region. Finally, it is proposed that turbulence production and pressure-strain spectra support the existence of the self-sustaining process as the main turn-over dynamics of all the energy-containing motions