Flow structures of mode-1 internal waves interacting with topographic ridges of varying slope and height

This research presents numerical simulations of the interaction of first-mode internal waves with a topographic ridge using nonhydrostatic simulations. Modifications are explored to both the amplitude of the internal wave and the topographic feature as a function of wave-topographic slope, the height of the topography and the wave Froude number (Fr=U₀/c_ph), where U₀ is the maximum velocity amplitude and c_ph is the linear first-mode internal wave phase celerity. Flows with higher wave Froude numbers show increased non-linear dynamics and similar formation of bolus cores as seen in DNS simulations at the laboratory scale and field observations. Conditions allowing for the formation of bores using linear theory are corroborated for these simulations at the intermediate scale, O(100 m). Bolus propagation past the ridge peak highlights a similarity to gravity currents, both in scaling and in the propagation dynamics. Topographic features with critical slopes enhance these overturning structures.