écoulements turbulents

A new approach to noise modeling for free turbulent flows is presented. A set of equations is derived from the acoustic variables. In the left-hand side of this system, one finds the linearized Euler equations, whereas the right-hand side exibits source terms. These source terms are modeled in using a stochastic space-time description of the three-dimensionnal turbulent motion. The linearized Euler equations including a stochastic description of noise sources are solved numerically. The Stochastic and Noise Generation (SWGR) model is appüed to a subsonic free jet. The weak interaction between the stationnary mean flow and the acoustic field is taken account. The limitations of the SNGR model lie in the statistical properties of the synthetic turbulent field and in the use of an axisymmetric modeling of the acoustic propagation.