Abstract
This paper presents an investigation of RANS and DES models for the Ahmed body with 25° and 35° slant angles. The Reynolds number, based on the height of the model and the upstream velocity, is 7.68× 105. Two RANS (Reynolds Averaged Navier–Stokes) models are used: the k−ω SST of Menter and the EARSM (Explicit Algebraic Stress Model), based on the k−ω model. Two hybrid RANS-LES (Large Eddy Simulation) models are used: a DES (Detached Eddy Simulation) and an IDDES (Improved Delay Detached Eddy Simulation). These hybrid models are also based on the k−ω model. The flow for the slant angle 35° is well predicted by all turbulence models with a slight advantage for the IDDES model. For the flow with the slant angle 25°, only the IDDES hybrid RANS-LES model predicts the recirculation bubble on the slant. It is concluded that the IDDES model is the only turbulence model that gives good agreements with the experimental data.
Highlights
The numerical simulation of complex external flows is an important component of automotive design
(a) Streamwise velocity component (b) Turbulent kinetic energy Figure 3: Time-averaged profiles obtained with the Improved Delayed Detached Eddy Simulation (IDDES) model in the symmetry plane for the 25◦ slant angle
The results obtained with the hybrid Reynolds Averaged Navier-Sokes (RANS)-Large Eddy Simulation (LES) models and presented show the mean flow
Summary
The numerical simulation of complex external flows is an important component of automotive design. Wind tunnel testing is still widely used but the need for reliable numerical tools is growing due to the relatively low cost associated with the numerical simulations. One of the major challenges in automotive industry, and in industrial applications in general, is the need of computational fluid dynamics (CFD) tools that simulate robustly and accurately 10 the flow physics. External flows for high Reynolds number are characterized by highly turbulent and three-dimensional separation and reattachment phenomena. The ability of a CFD simulation to capture correctly these flow features is strongly linked to the quality of the turbulence model
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
