Turbulence model study for aerodynamic analysis of the leading edge tubercle wing for low Reynolds number flows

A turbulence model study was performed to analyze the flow around the Tubercle Leading Edge (TLE) wing. Five turbulence models were selected to evaluate aerodynamic force coefficients and flow mechanism by comparing with existing literature results. The selected models are realizable k-epsilon, k-omega Shear Stress Transport (SST), (gamma - Re theta) SST model, Transition k-kl-omega model and Stress- omega Reynolds Stress Model (RSM). For that purpose, the TLE wing model was developed by using the NACA0021 airfoil profile. The wing model is designed with tubercle wavelength of 0.11c and amplitude of 0.03c. Numerical simulation was performed at chord-based Reynolds number of Rec = 120,000. The Computational Fluid Dynamic (CFD) simulation reveals that among the selected turbulence models, Stress- omega RSM estimated aerodynamic forces (i.e. lift and drag) coefficients closest to that of the experimental values followed by realizable k-epsilon, (gamma - Re theta) SST model, k-omega SST model and k-kl-omega model. However, at a higher angle of attacks i.e. at 16 degrees & 20 degrees k-omega SST model predicted closest drag and lift coefficient to that of the experimental values. Additionally, the critical observation of pressure contour confirmed that at the lower angle of attack Stress- omega RSM predicted strong Leading Edge (LE) suction followed by realizable k-epsilon, (gamma - Re theta)SST model, k-omega SST model and k-kl-omega model. Thus, the superiority of Stress- omega RSM in predicting the aerodynamic force coefficients is shown by the flow behavior. In addition to this pressure contours also confirmed that k-kl-omega model failed to predict tubercled wing aerodynamic performance. At higher angles of attacks k-omega SST model estimated aerodynamic force coefficients closest to that of the experimental values, thus k-omega SST model is used at 16 degrees & 20 degrees AoAs. The observed streamline behavior for different turbulence models showed that the Stress- omega RSM model and k-kl-omega model failed to model flow behavior at higher AoAs, whereas k-omega SST model is a better approach to model separated flows that experience strong flow recirculation zone.