Fifth International Symposium on Turbulence and Shear Flow Phenomena
DOI: 10.1615/TSFP5
PHASE SYNCHRONIZATION and IMPROVEMENT OF CONTROLLABILITY OF THE NEAR WALL TURBULENCE
pages 431-436
DOI: 10.1615/TSFP5.660
摘要
The effect of a spatially localized time-periodical perturbation on the controllability of the wall turbulence is analyzed. It is shown that the imposed unsteadiness with a frequency in the median production range doubles the controllability of turbulent drag. It is further observed that the spatially averaged turbulent wall shear is synchronized in time with the imposed perturbation waveform. This is related to the synchronization of the unstable periodic orbits present in the near wall turbulence in connection with the regeneration cycle of turbulence producing coherent structures.