DNS and scaling law analysis of compressible turbulent channel flow

Fully developed compressible turbulent channel flow (Ma = 0.8, Re = 3300) i s numerically simulated, and the data base of turbulence is established. Th e statistics such as density-weighted mean velocity and RMS velocity fluctu ations in semi-local coordinates agree well with those from other DNS data. High order statistics (skewness and flatness factors) of velocity fluctuat ions of compressible turbulence are reported for the first time. Compressib ility effects are also discussed. Pressure-dilatation absorbs part of the k inetic energy and makes the streaks of compressible channel flow more smoot h. The scaling laws of compressible channel flow are also discussed. The co nclusions are: (a) Scaling law is found in the center area of the channel. (b) In this area, ESS is also found. (c) When Mach number is not very high, compressibility has little effect on scaling exponents.