Application of a transition-sensitive two-equation turbulence model to CFD simulations of missile nose-cone geometries

This paper presents results from an ongoing effort to develop and validate a two-equation eddy-viscosity turbulence model for computational fluid dynamics (CFD) prediction of transitional and turbulent flow. The new model is based on a k-omega model framework, making it more easily implemented into existing general-purpose CFD solvers than other recently proposed model forms. The model incorporates inviscid and viscous damping functions for the eddy viscosity, as well as a production damping term, in order to reproduce the appropriate effects of laminar, transitional, and turbulent boundary layer flow. The new model has been implemented into a Mississippi State University (MSU) Computational Simulation and Design Center (SimCenter) developed flow solver (U2NCLE), as well as a commercially available CFD code (FLUENT). For model validation, comparisons were made to experimental data for an incompressible, zero-pressure gradient, flat plate geometry over a range of freestream turbulence quantities, using both of the flow solvers. Additional test cases were performed with the in-house flow solver and compared to experimental data for two sharp-cone geometries. The Mach number for the cone cases ranged from 0.4 to 2. The results presented in this document show that the new model performed well for the 2-D test cases and showed agreement with the experimental data of the 3-D geometries. The results illustrate the ability of the model to yield reasonable predictions of transitional flow behavior using a very simple modeling framework, including an appropriate response to freestream turbulence quantities.