The goal of this work is to study some numerical solutions of acoustic propagation problems using linearized Euler's equations. The two-dimensional Euler's equations are linearized around a stationary mean flow. The solution is obtained by using a dispersion-relation-preserving scheme in space, combined with a forth-order Run-ge-Kutta algorithm in time. This numerical integration leads to very good results in terms of accuracy, stability and low storage. The radiation of a source in a subsonic and supersonic uniform mean flow is investigated. The numerical estimates are shown to be in excellent agreement with the analytical solutions. Next, a typical problem in jet noise is considered, the propagation of acoustic waves in a sheared mean flow, and the numerical solution compares favorably with ray tracing. The final goal of this work is to improve and to validate the Stochastic Noise Generation and Radiation (SNGR) mode. In this model, the turbulent velocity field is modeled by a sum of random Fourier modes through a source term in the linearized Euler's equations. The implementation of acoustic sources in the linearized Euler's equations is thus an important point. This is discussed with emphasis on the ability of the method to describe correctly the multipolar structure of aeroacoustic sources. Finally, a nonlinear formulation of Euler's equations is solved in order to limit the growth of instability waves excited by the acoustic source terms.
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