Institut Jean Le Rond d'Alembert Unité Mixte de Recherche CNRS n°7190

Post-Doctoral Position "Numerical Simulation of Acoustical Wave Propagation in a Turbulent Atmosphere" Realistic noise prediction is a key factor for the environmental design of large scale applications, such as airports, ground transportations networks or industrial installations. Infrasonic acoustical waves due to meteores, volcano explosions, earthquakes, avalanches or sonic booms are also a potential way to survey the upper atmosphere and contribute to the monitoring of the global climatic evolution. In all these cases, acoustical waves propagate in the atmosphere, which is a turbulent medium, both near the ground in the planetary boundary layer, or in the upper atmosphere with internal gravity waves. Three dimensional fluctuations of the sound and flow speeds strongly disturb the sound field, by refracting, focusing and scattering the pressure waves. The objective of the proposed study is to contribute to the development of an efficient and precise numerical solver for linear and nonlinear sound waves in a turbulent atmosphere. In particular, one key objective is to implement numerically a new theoretical "one-way" formulation of wave propagation in a turbulent medium, that goes beyond the limitations of the parabolic approximation. Contemplated numerical methods include finite-differences, pseudo-spectral techniques and wavefront tracking. Simulations will be performed in coupling with atmospherical data provided by Large Eddy Simulations (LES) of the atmospheric planetary boundary layer. The post-doctoral position is proposed by Institut Jean Le Rond d'Alembert (www.dalembert.upmc.fr), in the research team MPIA (Modeling, Propagation and Acoustical Imaging) under the supervision of François Coulouvrat, CNRS Research Director ([email protected]) and Régis Marchiano, Assistant Professor ([email protected]) and in collaboration with Professor Pierre Sagaut for LES simulations (research team FRT – Reactive and Turbulent Fluids). The Institute is the major Mechanical Engineering Department at Université Pierre et Marie Curie – Paris 6 (www.upmc.fr), a leading Science and Medicine University in Europe, ideally located at the heart of Paris. UPMC is also one of the partners of the academic network Paris Universitas. The candidates to the post-doctoral proposal should have completed their PhD at the beginning of the project and are expected to have some research experience in numerical simulations in fluid mechanics and / or in acoustics. The position is proposed for one year, with possible prolongation. For non-French citizens, assistance will be provided to apply for accommodation at Cité Universitaire Internationale if requested. The start of the project is expected between 1st October 2008 and 31 March 2009. Contact François COULOUVRAT Email : [email protected] Tel : (33) (0)1 44 27 51 46 Fax : (33) (0)1 44 27 52 59