Effect of design changes in simplified trailer-truck geometry on aerodynamic drag coefficient

Energy efficiency and environmental sustainability in the transportation industry are increasingly important topics today. In this study, the aerodynamic design of transportation vehicles is considered an effective strategy for reducing fuel consumption and carbon dioxide emissions. Particularly, improving the aerodynamic performance of trucks holds significant potential in the transportation industry. This study investigates the effects of simplified trailer-tractor geometry design changes on aerodynamic drag coefficient, a crucial aspect in the transportation industry. The research progresses through comprehensive computer-aided design and analysis using Ansys 2023 R2 software. This study encompasses computational fluid dynamics analyses of 11 different variants for each of two different models (Model-A and Model-B) to understand the effects of using tractor deflectors and trailer tear-drop models on aerodynamic performance. Model-A represents a tractor with a sharp-edged upper surface, while Model-B represents a tractor with a rounded upper surface. Aerodynamic drag coefficients are calculated for each variant using Ansys Fluent software. Wind tunnel geometry is constructed for the analysis models, with a Reynolds number of 0.51x10^6 calculated, and the same boundary conditions are applied in 22 different analysis studies. According to the analysis results, for Model-A, the Cd value is measured as 0.709 for Variant 1, and 0.380 for Variant 11, which exhibits the highest geometric modifications. Thus, the percentage change in drag coefficient is calculated as 46.40%. For Model-B, the Cd value is determined as 0.711 for Variant 1 and 0.351 for Variant 11, showing the highest geometric modifications. Hence, the percentage change in drag coefficient is calculated as 56.53%.