Hi Dear friends. Here is a difficult question, I think!

I am using the SMAC method to solve turbulent free-surface fluid-flow problems. The boundary condition on rigid boundary is ready. In a moving free-surface, I am setting homogeneous Neumann type for K and Epsilon variables. This boundary condition is a first approximation. So, I would like to know if someone has sugestion.

Thanks.

I think you could look at some paper by B.A. Younis so as to how the free surface condition for Epsilon needs modelling.

Wolfgang Rodi devised an Epsilon boundary condition to account for the influence of the free surface on the turbulent length scale. It is described in:

W. Rodi, 'Turbulence models and their applications in hydraulics: A state of the art review', Book publication of IAHR, Delft, The Netherlands,(1980).

There are later editions of this book, and note that several variants of the Rodi condition have appeared in the literature.

Yes Herve. This is correct. This is a problem dependent. Michel, I think that this is what I am using. Note that, in my problems, there is a MOVING free-surface. Ferrerira.

Moving free surface and moving grid problems remind me of a paper by Tchamen and Kahawita (1998), although I'm not sure whether they mentioned all variable BCs... I think the thread of papers by Cokljat and Younis (1995) could still be interesting... I might have some more adequate material in my drawers. I'll try and post them later.

Yes Herve, it is very interesting. Please send me the references. Thanks. Ferreira.