Some aspects of the thermal mixing layer in grid turbulence

Abstract

By generating a temperature step in grid turbulence using two new methods (a mandoline and a toaster) the evolution of some first-, second-, third-, and fourth-order moment quantities of the temperature field in a thermal mixing layer are studied. The results confirm the earlier experimental findings of LaRue and Libby [Phys. Fluids 24, 597 (1981)] and LaRue et al. [Phys. Fluids 24, 1927 (1981)] who used a half-heated grid to generate the thermal field. It is also shown that although second-order quantities such as the heat flux coefficient and the centerline temperature variance appear to have reached their equilibrium values and that all quantities collapse well using the half-width of the mean temperature profile, the data is not consistent with self-similarity.