Development of an Aerodynamic Analysis Methodology for Tractor-Trailer Class Heavy Commercial Vehicles

An aerodynamic analysis methodology which makes efficient use of ANSA and FLUENT software's in the aerodynamic design of tractor-trailer class heavy commercial road vehicles is presented. The aerodynamic drag coefficient of the truck is used as the main control parameter to evaluate the performance of the methodology. Analysis methodology development activities include determining optimal FLUENT software analysis parameters for the defined problem (RANS based turbulence models, wall boundary layer models, solution schemes) and the necessary ANSA mesh generation parameters (boundary layer number and growth rate, wall surface mesh resolution, total mesh resolution). Proposed methodology is first constructed based on CFD simulations for the zero-degree yaw angle case of the 1/8 sized GCM geometry. The present results are within 1% of the experimental data. The know-how and experience gained, then, used to define an optimal analysis methodology for GCM test model with the optimal analysis and mesh generation parameters. Finally, the optimal analysis methodology of the GCM model is adapted to a recent Ford heavy vehicle geometry. The FORD heavy road vehicle CFD result is within 1% of the vehicle test result. Detailed calculations are obtained within 2 days using the FORD HPC system. Somewhat less accurate results may be obtained within few hours' time using the same HPC resources.