Assessment of the performance of different classes of turbulence models in a wide range of non-equilibrium flows

Highlights: • Thirteen turbulence models have been assessed in classical non-equilibrium flows. • Homogeneous shear flows have been shown to challenge turbulence models. • RST models return reasonable turbulence fields, but not always the mean flow fields. • All models were unable to predict the reattachment point in oscillatory step flows. • Re-optimisation across the range of test cases could bring some model improvements. - Abstract: The performance of thirteen benchmark turbulence models within the RANS framework has been assessed in classical non-equilibrium flows. Linear and non-linear eddy-viscosity schemes, Reynolds stress transport models and single- and two-time-scale approaches have been considered in the investigation. Among the test cases studied are homogeneous shear and normally strained flows, adverse-pressure-gradient, favourable-pressure-gradient and oscillatory boundary layer flows, fully developed oscillatory and ramp up pipe flows and steady and pulsated backward-facing-step flows. The main advantages and drawbacks of the models in each of the test cases are discussed. These discussions provide a reasonably wide understanding of the expected behaviour of the models for future applications in non-equilibrium flows, and also result in suggestions on how the effectiveness of existing models can be further improved