Technical Paper
Numerical Simulations of High-Fidelity Class 8 Semi-Trailer Truck Geometries and Comparison with Wind-Tunnel Data
2024-04-09
2024-01-2533
This article analyzes the aerodynamic performance of high-fidelity Class 8 tractor-trailer geometries provided by the Environmental Protection Agency (EPA). Computational fluid dynamics (CFD) simulations are conducted using Simerics-MP+, a finite-volume pressure-based solver equipped with an enhanced RANS k-ϵ turbulence model. Two different tractors are considered: the Day Cab, and the Sleeper Cab, both featuring detailed underbody, open-grille under-hood engine compartment, mirrors, and two porous-media volumes to model the pressure-drop effects caused by the radiator and condenser. Simulations are set considering realistic driving conditions: with lateral wind, rotating wheels, and moving floor. Meshing is performed directly on the provided geometry, without requiring any type of preprocessing, by using the Simerics Binary-Tree mesher, which produces a body-fit unstructured grid. Multiple tractor/trailer variants are studied by adding aerodynamic surfaces to the baseline geometries.