I am modelling an island surrounded on all sides by ocean, with the island at the center of the grid.

​​​​​​​The model works ok when forced with astronomical water levels only (tidally driven) but I want to use the same grid for a wind-forcing only simulation.  When I run the FLOW model without any boundary conditions (just a steady wind comprised of a uniform x-field and y-field) the resulting flow runs parallel to the edge of the grid, following the edges round in a loop (like the boundary is solid). What boundary conditions need imposing to prevent this effect?

Thanks in advance for any help.