Comparison and validation of various turbulence models for U-bend flow with a magnetic resonance velocimetry experiment

Turbulence modeling plays an important role in the accurate prediction of turbulent fluid motion in computational fluid dynamics simulations using the Reynolds-averaged Navier-Stokes equations. A new one-equation Wray-Agarwal (WA) turbulence model has recently been developed by the present authors to improve the prediction of nonequilibrium turbulent flows with large separation and curvature. In this paper, the WA turbulence model is employed to simulate the internal turbulent flow characteristics in a U-bend, and the computed results are compared with experimental data. The results obtained from four other commonly used turbulence models, viz., the one-equation Spalart-Allmaras, two-equation standard k-epsilon, renormalization group k-epsilon, and shear stress transport k-omega models, are also compared. Detailed experimental data are obtained using magnetic resonance velocimetry. The results computed with the five different turbulence models show that the WA turbulence model gives the highest accuracy in predicting the complex three-dimensional turbulent characteristics of flow with large curvature in a U-bend.