Quantitative Relative Comparison of Cfd Simulation Uncertainties for a Transonic Diffuser Problem

Different sources of uncertainty in CFD simulations are illustrated by a detailed study of two-dimensional, turbulent, transonic flow in a converging-diverging channel. Runs were performed with the commercial CFD code GASP using different turbulence models, grid levels, and flux-limiters to see the effect of each on the CFD simulation uncertainties. Two flow conditions were studied by changing the exit pressure ratio: the first is a complex case with a strong shock and a separated flow region, the second is the weak shock case with no separation. The uncertainty in CFD simulations has been studied in terms of four contributions: (1) discretization error, (2) error in geometry representation, (3) turbulence model, and (4) the downstream boundary condition. In this paper, we ∗Corresponding author. Department of Aerospace and Ocean Engineering, 215 Randolph Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0203, USA. Phone: 1-540-2307717, Fax: 1-540-2319632, e-mail: [email protected]