RESEARCH Received: 18 July 2024 / Accepted: 15 March 2025 © The Author(s), under exclusive licence to Springer Nature B.V. 2025  Odenir de Almeida odenir.almeida@ufu.br 1 Experimental Aerodynamics Research Center (CPAERO), Faculty of Mechanical Engineering, Federal University of Uberlandia, Uberlandia, MG, Brazil 2 School of Aerospace, Transport and Manufacturing, Cranfield University, Cranfield, UK Experimental and Numerical Investigation of Scale Effects on the Flow Over a Sedan Vehicle Guilherme Espíndola da Silva 1  · Rafael Rezende Dias 1  · Odenir de Almeida 1  · Anderson Ramos Proença 2 Flow, Turbulence and Combustion https://doi.org/10.1007/s10494-025-00651-w Abstract Experiments and numerical modeling on vehicle aerodynamics were conducted in a Reyn- olds (Re) number one order of magnitude lower than that of typical full-scale applica- tion. Drag coefficient, velocity profile measurements and flow visualization were the focus with the proposition of comparing scale effects of a 1:10 sedan passenger vehicle model with numerical data from full-scale (1:1) based on the Reynolds Averaged Navier–Stokes (RANS) approach. After the validation of the numerical approach at 1:10 scale, additional investigation of sharp and rounded fillets presented on the car’s geometry showed to be relevant to the calculation of the separating shear layers and drag prediction, although the general wake structures are qualitatively similar. Effects of the reduced scale are translated to low Reynolds number where viscous effects starts to play a role. Detailed flow features such as recirculating regions and reversing flow acts on the model’s surface while the near wake velocity field is well captured and evaluated both experimentally and numerically. The results permitted to characterize flow details based on Re number flow, to show the effects of sharp corners on the model and to scrutinize the influence of scale effects on vehicle’s aerodynamics. Highlights ● Experimental wind tunnel and numerical modeling on a generic vehicle aerodynamics. ● Comparison of aerodynamic results between 1:10 and 1:1 scale. ● Friction drag influence due to scale effects. ● General and wake flow under Reynolds number effect. Keywords Reynolds effect · Scale model · Car aerodynamics · Sedan vehicle · Aerodynamics 1 3