Two-equation turbulence models for smooth oscillatory boundary layers

Six two-equation turbulence models, comprising three versions from k - ε group and the same number of k - ω model versions, have been tested against the direct numerical simulation (DNS) data for a boundary layer under slowly varying ID oscillatory flow. A detailed comparison has been made for mean velocity, turbulent kinetic energy, Reynolds stress, and bottom shear stress. A quantitative comparison is made in the cross-stream direction using the correlation between DNS data and the model predictions. It is observed that the later versions of the k - ε model perform very well by virtue of the mean velocity, turbulent kinetic energy, and Reynolds stress. The friction factor, phase difference, and boundary layer thickness have been predicted by one of the k - ω models in a better way. This study may be helpful in choosing a suitable model for a specific practical application in coastal environments.