Numerical simulations of aerodynamically generated sound from aircraft noise sources using the lattice Boltzmann method
Prof. Luc Mongeau
Department of Mechanical Engineering, McGill University, Canada
LOCAL: Centro de Tecnologia, Bloco G, sala 205
ABSTRACT: Aircraft noise remains an important environmental problem, exacerbated by increased traffic and the sprawl of residential areas around airports. Noise control at the source remains the best approach to limit noise emissions. Many sources of sound are asssociated with turbulent flows past the airframe or through the engine nozzles. Direct numerical simulations are used to attempt the prediction of such radiated sound levels from first principles, through time marching solutions of the fluid flow governing equations, with the long term goal of designing more effective suppression devices. Most numerical methods for the prediction of aerodynamic noise are based on the solution of the Navier Stokes (NS) method. Such numerical solutions are very costly and are not yet possible for realistic aircraft component geometries. For low Mach number flows, one alternative is the lattice Boltzmann method (LBM). The LBM models the flow field in the so-called mesoscopic scale, between the macroscopic (NS) and the microscopic (Boltzmann´s equation) scales. In recent work, flow simulations were obtained using the LBM for flows through lobed mixers, flows around fully dressed landing gears, and flow over slat gaps. Noise from cold jets with and without microjet suppression devices was investigated. The influence of temperature was also examined through the use of a hybrid LBM-thermal model. In this talk, the basic principles behind the LBM will be discussed. Several application case studies will be summarized and an outlook for further applications for high velocity, compressible flows will the offered.