The Lattice-Boltzmann Method: An Alternative to LES for Complex Aerodynamic and Aeroacoustic Simulations in the Aerospace Industry

An overview of the theory and applications of the Lattice-Boltzmann Method (LBM) is presented in this paper. LBM has gained a reputation over the past decade as a viable alternative to traditional Reynolds-averaged Navier-Stokes (RANS) based methods for the solution of computational fluid dynamics (CFD) applications in the aerospace and automotive industries. The theoretical background of the method is presented and the key differentiators to traditional RANS methods are summarized. We then look at current and potential future applications of CFD in the aerospace industry and identify a number of areas where the limitations of RANS tools, in particular with regard to unsteady flows and the handling of complex geometries, prevent a deeper penetration of CFD into product development processes in the aerospace industry. Hybrid RANS/LES and full LES methods are the main areas of CFD research today to overcome the limitations of RANS methods but are also subject to limitations that have prevented widespread industrial use to date. We show that the Lattice-Boltzmann method presents a realistic alternative to these approaches and demonstrate this through a number of industrial simulations for aerodynamics, aeroacoustics and thermal applications, all validated against reliable experimental data. Finally, we present an outlook towards the simulation of some of the Grand Challenge problems in aerospace, such as the simulation of a powered aircraft configuration across the full flight envelope, and show that the Lattice-Boltzmann method offers the promise to reach these goals in a far shorter time frame than will be possible with traditional CFD methods.

All examples presented in this paper were simulated using the commercial LBM code PowerFLOW developed by Exa Corporation.