Assessment of flow and force predictions on representative high-sided vehicles at multiple yaw angles using SST-DDES

Purpose This paper aims to evaluate the capabilities of the k-ω shear stress transport delayed detached-eddy simulation (SST-DDES) model for predicting the flow field around two benchmark high-sided vehicles – ranging from a highly simplified generic body to a near-realistic truck – across several discrete yaw angles. It also explores whether specific turbulence modeling modifications can enhance accuracy under large-yaw conditions. Design/methodology/approach Flow around the ground transportation system (GTS) and Leyland DAF 45-130 models was simulated. Initially, a standard SST-DDES formulation was adopted. To improve accuracy at large yaw, two modeling strategies were explored: (i) tuning a key parameter of the SST model (a1) and (ii) adopting a nonlinear constitutive relation for the Reynolds stresses. Results were assessed in terms of key flow structures, aerodynamic forces and surface-pressure and skin-friction coefficients. Wind tunnel data were used as reference. Findings SST-DDES yielded good agreement for the GTS, with improved predictions at high yaw when moderately increasing the a1 parameter. For the more complex Leyland model, predictions were generally consistent with experiments, though the influence of model variants was negligible and some results fell marginally outside experimental uncertainty, reflecting intrinsic limitations of the SST-DDES formulation. Originality/value To the authors’ knowledge, this is the first numerical study that simultaneously (i) evaluates flow predictions over high-sided vehicles ranging from a simplified to a near-realistic model, (ii) covers multiple discrete yaw angles and (iii) assesses different turbulence modeling strategies under large-yaw conditions.