Modelling of Stationary Three-Dimensional Separated Air Flows around an Ahmed Reference

Abstract: When analysing the topology of turbulent flow systems for alternative vehicle configurations, conventional wind-tunnel tests may not be sufficient. Vehicle development teams investigating this kind of physical phenomenon are increasingly interested in numerical simulation, but reliable implementation of computational techniques in automotive aerodynamics requires validation to confirm that such methods are capable of accurately reproducing experimentally proven physical behaviour. We address this issue by comparing the results of experimental wind-tunnel tests with simulated values for aerodynamic drag coefficient and vortex wake flows at different angles of car rear window inclination, using an Ahmed [1] reference model. To meet targets for shorter lead-times and lower costs in modern automobile design processes, aerodynamics specialists are constantly seeking new solutions capable of providing prompt and accurate guidance in design practice. One such solution is numerical simulation, which provides a valuable complement to results obtained from experimenta