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COBEM 2023
27th International Congress of Mechanical Engineering
VALIDATION AND VERIFICATION OF AN OPEN-SOURCE CFD CODE FOR THE AERODYNAMICS SOLUTION OF AIR AND GROUND VEHICLES
Submission Author:
Guilherme Espíndola , MG
Co-Authors:
Guilherme Espíndola, Odenir de Almeida
Presenter: Guilherme Espíndola
doi://10.26678/ABCM.COBEM2023.COB2023-0272
Abstract
This work aims to present data in order to compare two Computational Fluid Dynamics (CFD) software: the commercial ANSYS Fluent and the open-source OpenFOAM, using experimental test data as a reference. This research seeks to validate OpenFOAM as a CFD tool for incompressible, steady-state external flow models. The study focuses on the aerodynamics of the Ahmed body with a 25° tilt angle and an air velocity of 40 m/s, resulting in a Reynolds number of 2.859 × 106 (based on the length of the body, which is 1.044 m). The focus of this work is built upon turbulence models, computational time, the influence of the mesh element count, and how all these configurations can affect the prediction of drag coefficient and velocity profiles. The adopted methodology consists of two steps, with the first being a mesh test in both software, varying the number of elements from 2 to 5 million. The second step investigates the influence of turbulence models: SST k-Omega, Realizable k-Epsilon, and Spalart-Allmaras. The results showed similar trends in velocity profiles but diverged with the Realizable k-Epsilon turbulence model. OpenFOAM achieved good accuracy with the SST k-Omega model, showing an error of 2.02% compared to ANSYS Fluent is 3.35% . However, OpenFOAM was four times slower. Furthermore, the use of the Spalart-Allmaras turbulence model resulted in an unfeasible error of over 50% .
Keywords
CFD, OpenFOAM, Turbulence Model, Open Source, Validation
