Flow through a curved duct using nonlinear two-equation turbulence models

Standard isotropic and nonlinear two-equation turbulence closures are employed to calculate the flow through a 90-deg rectangular duct. The models used include the two-layer k-ε model, the k-ω model, and two nonlinear variants of the k-ω model based on quadratic and cubic constitutive relations, respectively. Comparisons of the computed results with the measurements show that the cubic nonlinear k-ω closure is the only model that successfully reproduces most of the experimentally observed features of both the mean flow and turbulence fields. This work demonstrates, for the first time, that near-wall, nonisotropic, two-equation models offer a promising alternative to Reynolds-stress transport closures for developing practical computational fluid dynamics methods able to predict complex shear flows of engineering interest.