Structures and Multipoint Correlators for Turbulent Advection: Predictions and Experiments

We present theoretical predictions and wind tunnel measurements of the 3-point correlator of fluctuating temperature in preheated turbulent flow. The dependence of this passive scalar correlator on the point configuration is calculated on the basis of a model Hopf operator describing its time evolution but can be understood in terms of the underlying frontlike structure of the temperature field. Model predictions reproduce the main features observed in experiment. The geometric insight into the structure of the fluctuating field provided by multipoint correlators suggests new approaches to the study of turbulence itself.