Reduced-Order Model for Near-Wall Turbulence and Its Application

The self-sustaining process (SSP) consisting of streaks and streamwise vortices in the near-wall region is an important mechanism for the generation and maintenance of wall-bounded turbulence. In the present study, the flow field of near-wall SSP was obtained by direct numerical simulation of the minimal flow unit and analyzed by using proper orthogonal decomposition(POD). POD modes on different streamwise and spanwise scales were obtained and the reduced-order model (ROM) of SSP was derived by projecting the Navier-Stokes equations on these modes. The prediction ability of the ROM was validated by DNS data. The ROM has been preliminarily applied on the construction of the wall models for large eddy simulation.