Comparative CFD Analysis of SST k–ω and Spalart–Allmaras Turbulence Models for Aerodynamic Force Prediction of a Grid-Fin Missile at Mach 2.5 and 10° Angle of Attack

Abstract

The aerodynamic performance of aerospace vehicles operating in supersonic flow regimes is significantly influenced by the accurate prediction of complex flow phenomena, flow separation and turbulent boundary-layer interactions. The present study investigates the aerodynamic characteristics of the selected configuration under supersonic flow conditions at a constant angle of attack of 10°. A comparative Computational Fluid Dynamics (CFD) analysis is performed using two turbulence models, namely the SST k-ω model and the Spalart-Allmaras (SA) model. The numerical simulations are carried out to evaluate the influence of turbulence-model selection on the prediction of the aerodynamic flow field and force characteristics at 2.5 Mach number. Particular emphasis is given to the axial force coefficient and normal force coefficient, which are important parameters for assessing the aerodynamic performance and stability of high-speed vehicles. The computational results obtained using both turbulence models are compared through aerodynamic performance plots to identify variations in force prediction across the investigated Mach number range. The analysis demonstrates the capability of both turbulence models to capture the essential characteristics of supersonic flow. However, differences in the predicted aerodynamic coefficients are observed due to variations in their turbulence-modelling approaches and their ability to represent shock-boundary-layer interactions. The SST k–ω model provides enhanced capability in resolving near-wall flow and adverse pressure-gradient effects, whereas the Spalart–Allmaras model offers a computationally efficient approach for aerodynamic simulations. The comparative results provide valuable insight into the suitability of these turbulence models for the prediction of aerodynamic forces under supersonic flight conditions. The findings of this study can contribute to the selection of appropriate turbulence models for the aerodynamic design and numerical analysis of high-speed aerospace configurations.