Effect of Finite-rate Chemical Reactions on Turbulence in Hypersonic Turbulent Boundary Layers

We conduct direct numerical simulations of reacting turbulent boundary layers to study the effects of finite-rate chemistry on turbulence as well as turbulence-chemistry interaction. It is found that turbulence fluctuations have a relative large influence on the dissociation reaction, while have a subtle influence on the recombination reaction. The influence of chemical reactions on temperature fluctuation variance, Reynolds stresses and turbulence kinetic energy is analyzed, and the results are compared with the non-reacting case. We find that the recombination reaction enhances turbulence, while the dissociation reaction damps turbulence. Chemical reactions influence the velocity field mainly by the heat of reaction, which causes volumetric flow expansion/contraction. The correlation of temperature fluctuation and fluctuation in species composition is significantly enhanced, and temperature fluctuations cause large fluctuations in species composition.