Aerodynamic study of a moving Ahmed body by numerical simulation

Abstract

An aerodynamic analysis of the Ahmed body in motion is presented in this work. The goal is to investigate the effect of motion on aerodynamic forces with the aim of generating useful information for reducing drag energy consumption and improving stability and comfort. The research is carried out using finite volume computational simulation with the OpenFOAM(R) libraries. Using the well-known benchmark for a fixed Ahmed body geometry, the numerical model is validated with experimental data. A hybrid RANS-LES turbulence model is employed and achieves an excellent level of agreement. The Ahmed body is then simulated under dynamic conditions, using a spectrum of frequencies and amplitudes corresponding to typical heaving motion observed in passenger cars. Furthermore, a quasi-dynamic model is proposed and evaluated to reduce the computational cost of dynamic simulations. The results of the dynamic study differ significantly from those of the static study, demonstrating that vertical velocity, position, and flow inertia have a major impact. The evaluated quasi-dynamic model may not precisely capture quantitative values, but it provides insight into the general trend of aerodynamic forces throughout the oscillation cycle.