# Sound Scattering on a Turbulent, Weakly Heated Jet

Abstract : We report an experimental study of the scattering of ultrasonic plane waves on a turbulent jet in air Pr = 0.7. The jet is weakly heated so that the temperature fluctuations act as a passive scalar. In the backscattering geometry one measures the Fourier components of the temperature field $\tilde{T}q, t$. The time averaged characteristics are analyzed in detail; in particular we observe a Kolmogorov -5-3- power law behavior for the passive scalar spectrum in the inertial range of scales. The study of the time fluctuations shows that the histograms of $\tilde{T}q, t$ remain close to a Gaussian at all scales.

Author: A. Petrossian J.-F. Pinton

Source: https://hal.archives-ouvertes.fr/