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Hi,
I have a model over a bay for which I try to simulate currents. The model has a varying wind and water level (at the outer boundary).

My problem is that I get an oscillation of the water surface in the inner part of the bay. See attached figure. Why do I get this oscillation and how do I get rid of it? I'm also attaching the cas-file.





Best regards,
/Björn

Hello,

This is strange, aren't you triggering a resonance in the bay, because the period seems rather large, it does not look like numerical oscillations (unless you see SPATIAL oscillations of the free surface at a given time step).

Anyway I would choose to have a rough regime for the bottom (TURBULENCE MODEL FOR THE BOTTOM = 2). This name has been changed into TURBULENCE REGIME FOR THE BOTTOM in the enxt version because it is misleading.

Otherwise I do not think that k-epsilon can be very effective in a large bay with large elements, you can try also a constant coefficient on the horizontal, with coefficient at least 1 in your case, and a mixing-length on the vertical.

As the elements are smaller in the inner bay, looking at the effect of the time-step (a larger or smaller) would also give a hint.

With best regards,

Jean-Michel Hervouet