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The lattice Boltzmann (LB) method has been successfully used in conjunction with a Very Large-Eddy Simulation (VLES) turbulence modeling approach for over a decade for the accurate prediction of automotive fluid dynamics. Its success lies in the unique underlying physics that is significantly different from traditional computational fluid dynamics methods. In this paper, we provide a complete description of the method followed by a set of examples which show its use in the automotive industry. We will first provide a review of the physics and numerical methods. Here the LB method and its relationship to kinetic theory and the Navier-Stokes equations will be briefly discussed. We will summarize the strengths of LB method, especially for the solution of transient flows in extremely complex geometries. The VLES turbulence modeling method will be presented next, as well as how VLES neatly fits into the LB framework.

Aerodynamic simulations of a 1:8-scale simplified tractor-trailer, designated as the Generic Conventional Model (GCM), were conducted using a Lattice-Boltzmann based solver. Comparisons were made to experimental measurements from the NASA Ames 12-Foot Pressure Wind Tunnel, including drag coefficients as a function of yaw, static and transient surface pressures, and three-component particle image velocimetry. The baseline model configuration was tested at yaw angles from 0 to 12 degrees, allowing the calculation of the wind-averaged drag coefficient. Results demonstrated that the simulation predicted body-axis drag within experimental uncertainty and also resolved the correct pressure distribution and flow structure in the separated flow regions including the tractor-trailer gap and trailer wake regions. The comparison of the experimental transient pressure spectra showed good agreement with the simulation results, both in magnitude and identification of dominant spectral peaks.