Publications

Development of a one-equation transition/turbulence model

Edwards, J.R.; Roy, C.J.; Blottner, Frederick G.; Hassan, H.A.

The development of a unified one-equation model for the prediction of transitional and turbulent flows is described herein. An eddy-viscosity-transport equation for nonturbulent fluctuation growth based on that proposed by Warren and Hassan (Warren, E. S, and Hassan, H. A., "Transition Closure Model for Predicting Transition Onset" Journal of Aircraft, Vol. 35, No. 5, 1998, pp. 769-775) is combined with the Spalart-Allmaras one-equation model for turbulent fluctuation growth. Blending of the two equations is accomplished through a multidimensional intermittency function based on the work of Dhawan and Narasimha (Dhawan, S., and Narashima, R., "Some Properties of Boundary Layer Flow During Transition from Laminar to Turbulent Motion, " Journal of Fluid Mechanics, Vol. 3, No. 4, 1958, pp. 418-436). The model predicts both the onset and extent of transition. Low-speed test eases include transitional flow over a flat plate, a single-element airfoil, a multielement airfoil in landing config uration, and a circular cylinder. Simulations of Mach 3.5 transitional flow over a 5-deg cone are also presented. Results are compared with experimental data, and the spatial accuracy of selected predictions is analyzed.