Abstract: Under the specific flying condition, the interaction between turbulence and chemical nonequilibrium will exist on the surface of the vehicles, but the related research is still very limited. The flow state after the leading shock of a cone is chosen, and two gas models, i.e. the calorically perfect gas and the chemical reaction gas are utilized for the DNS study. The effects of chemical nonequilibrium on the turbulence statistics and fluctuations are analyzed, and the scaling law are investigated. The results show that the endothermic dissociated reaction is dominant in the boundary layer, which leads to the significant decreasing of the averaged-temperature and temperature fluctuation. But the effects of chemical nonequilibrium only have a little influence on the averaged streamwise velocity, velocity fluctuation and Reynold stress. In the log-region, the ESS of the fluctuations are still consistent with the scaling law.

Key words: Hypersonic flow, High-temperature, Turbulent boundary layer, Chemical nonequilibrium, DNS, Scaling law