Papers by Keyword: Turbulence Modelling

Abstract: Using the appropriate procedure, Computational Fluid Dynamics allows predicting many things in several fields, and especially in the field of renewable energies, which has become a promising research axis. The present study aims at highlighting the influence of the curvature correction on turbulence models for the prediction of the aerodynamic coefficients of the S809 airfoil using the Computational Fluid Dynamics code ANSYS Fluent 17.2. Three turbulence models are used: Spalart-Allmaras, Shear Stress Transport k-ω and Transition SST. Experimental results of the 1.8 m × 1.25 m low-turbulence wind tunnel at the Delft University of Technology are used in this work for comparison with the numerical results for a Reynolds number of 10⁶. The results show that the use of the curvature correction improves the prediction of the aerodynamic coefficients for all the turbulence models used. A comparison of the three models is also made using curvature correction since it gave better results. The Transition SST model is the one that gives the best results for the lift coefficient, followed by the Shear Stress Transport kω model, and finally the Spalart-Allmaras model. For the drag coefficient, Transition SST model is the best, followed by the Spalart-Allmaras model, and finally the Shear Stress Transport kω model.

Abstract: The simulation of a turbulent wall jet flow over a rectangular cavity is realised by the low Re stress-omega model. FLUENT 6.3 CFD code was used as the solver. The structured grid was built using Gambit 2.3. A preliminary study of a wall jet flow and a wall jet backward facing step interaction has been undertaken to validate the turbulence model. The numerical approach reproduces fairly the experimental results. A wall jet flow over rectangular cavities of different aspect ratios was investigated. The cavity aspect ratio effect on the flow structure evolution, particularly on the reattachment phenomenon, was examined in this paper. The results of this study show that the flow structure is very sensitive to the cavity aspect ratio. The reattachment length in the wall jet incoming flow case is very short compared to that of the boundary layer incoming flow case.