Large scale structure in inner and outer layers of turbulent channel flow revealed through large-scale DNS

摘要

A review of the direct numerical simulation of turbulent channel flow is presented. Intensive efforts have been directed to raise the Reynolds number. The increase of the Reynolds number in these 15 years is still less than ten times. This is because a precise DNS requires a larger mesh number with the third power of the Reynolds number. Another direction of the effort was devoted to enlarge the computational domain. Results of DNS with a larger domain revealed the existence of a large structure in the central region of the channel flow. A characteristic wavelength of the large scale structure is discussed. The study also indicated that the large scale structure in the outer layer affects the structure of the inner layer, too.