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Airflow over the Ahmed body is simulated by means of the Embedded LES technique. This is a zonal approach which allows the LES turbulence model to be used in a sub-domain while the rest of the domain is solved using a RANS turbulence model, i.e., the kω-SST model. This allows the LES zone to be restricted to the rear end of the vehicle where the unsteadiness of the flow must be accurately predicted. A comparison with full RANS modeling and experiments is reported.

In hybrid and electrical vehicles new challenges in meeting the drivers' expectation with regards to acoustic comfort arise. The absence of the internal combustion engine noise enhances the passengers' perception of other noise sources, such as the Heating, Ventilation and Air-Conditioning (HVAC) system. Therefore efficient and reliable numerical models able to predict flow-induced broadband noise have become a major research topic in automotive industry. In this framework, the Zonal LES coupled with the Ffowcs Williams-Hawkings (FWH) acoustic analogy are capable to simulate broadband noise from low speed axial fan. As demonstrated in previous works from the authors, this approach is able to cope with the complexity of the physical phenomena involved (i.e. turbulent noise generation, laminar-to-turbulent transition, etc.), even though the numerical model requires a careful setup of the mesh topology, boundary conditions and simulation parameters.