Turbulence during the generation of internal tide on a critical slope.

Three-dimensional direct numerical simulations are performed to examine nonlinear processes during the generation of internal tides on a model continental slope. An intense boundary flow is generated in the critical case where the slope angle is equal to the natural internal wave propagation angle. Wave steepening, that drives spanwise wave breaking via convective instability, occurs. Turbulence is present along the entire extent of the near-critical region of the slope. The turbulence is found to have a strong effect on the internal wave beam by distorting its near-slope structure. A complicated wave field with a broadband frequency spectrum is found. This work explains the formation of boundary turbulence during the generation of internal tides in the regime of low excursion numbers.