Transient Scale Resolved Simulations, like the Detached Eddy Simulation, are currently seen to be the preferred modeling approach over the steady-state Reynolds Averaged Navier-Stokes (RANS) simulations for numerical investigations of external flow due to the former’s perceived capability of providing a more realistic flow field prediction. However, the latter approach is still a widely used methodology in road vehicle aerodynamic developments because of its faster turn-around time and cost-effectiveness. However, RANS models, like the SST k–ω, generally fail to produce well-correlated predictions. Studies reveal that good correlations with experiment cannot be achieved by simply refining the mesh when using the SST k–ω model. As such, this study explores the possibility of improving the prediction veracity by investigating the influence of a few selected model closure coefficients on the CFD prediction. This involves first identifying the effect of each individual model parameter on the prediction, and then formulating the best combination of the model closure coefficient values that yield the best correlation with the experiment. This procedure is applied to three different test objects: NACA 4412 airfoil at 12 degree angle of attack, the 25 degree slant angle Ahmed body, and a full-scale passenger road vehicle. Although some closure coefficients do not influence the CFD results much, the predictions are very sensitive to the choice of certain model constants, irrespective of the test object geometry. The study also shows that it is possible to formulate a combination of closure model coefficients that can produce very well correlated CFD predictions.

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