fs82 |
December 19, 2011 05:04 |
Implementation of a relaxation boundary condition
Hello Foamers,
I would like to implement a new boundary condition for open boundaries for my LES. I found a well written paper of Palma and Matano (1998) "On the implementation of passive open boundary conditions for a general circulation model: The barotropic mode". They suggest various types of passive open boundary treatments, e.g. a radiation condition (named advectiveBC in Openfoam) or the one I am interested in: relaxation methods. The basic equation looks as follows:
, the relaxation parameter varies from 0 at the inner edge to 1 at the boundary, the reference state and the unrelaxed value. The bc treatment requires for my understanding write access to the internal velocity field. My question is now: where is the best starting point? Would it be better to implement it as a boundary condition or as a wall function? May be it is also an opportunity to add it as a additional volume force to the navier stokes equation? Thanks for your suggestions in advance.
kind regards,
Fabian
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