In certain flow models the turbulence closure in the vertical is different than in the horizontal. Other models neglect also the transport equation of turbulence energy and dissipation in the horizontal. I would be keen to get some info with respect to the different approaches in the different models. So everybody who developed a model or has good knowledge about a certain model is kindly invited to explain certain approaches used in the various models in order to get some overview. I hope we can have soon a complete list with a following discussion.