The capability of Large Eddy Simulations (LES), Improved Delayed Detached Eddy Simulations (IDDES) and Reynolds-Averaged Navier–Stokes Equations (RANS) to predict the flow behind notchback Ahmed body is investigated in the present paper. Simulations consider two specific models, with effective backlight angles of β1 = 17.8◦ and β2 = 21.0◦, respectively. The focus of the study is on the prediction of the expected lateral asymmetry or symmetry of the near-wake flows. Results show that IDDES using coarse computational grids predicts the flow in agreement with LES using finer computational grids. RANS results in inaccurate flow pre- dictions, attributed to its steady formulation relying on turbulence modelling being incapable of dealing with the studied flow. Modal analysis applying Proper Orthogonal Decomposition (POD) suggests the consistency of the wake dynamics between IDDES and LES. The presence of the wake bi-stability is validated by the wind tunnel experiment
He, K., Minelli, G., Wang, J., Gao, G., Krajnović, S. (2021). Assessment of LES, IDDES and RANS approaches for prediction of wakes behind notchback road vehicles. JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS, 217, 1-17 [10.1016/j.jweia.2021.104737].
Assessment of LES, IDDES and RANS approaches for prediction of wakes behind notchback road vehicles
Minelli, Guglielmo;
2021
Abstract
The capability of Large Eddy Simulations (LES), Improved Delayed Detached Eddy Simulations (IDDES) and Reynolds-Averaged Navier–Stokes Equations (RANS) to predict the flow behind notchback Ahmed body is investigated in the present paper. Simulations consider two specific models, with effective backlight angles of β1 = 17.8◦ and β2 = 21.0◦, respectively. The focus of the study is on the prediction of the expected lateral asymmetry or symmetry of the near-wake flows. Results show that IDDES using coarse computational grids predicts the flow in agreement with LES using finer computational grids. RANS results in inaccurate flow pre- dictions, attributed to its steady formulation relying on turbulence modelling being incapable of dealing with the studied flow. Modal analysis applying Proper Orthogonal Decomposition (POD) suggests the consistency of the wake dynamics between IDDES and LES. The presence of the wake bi-stability is validated by the wind tunnel experimentI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
