Turbulence during the reflection of internal gravity waves at critical and near-critical slopes

Abstract

Direct numerical simulation is performed with a focus on the characterization of nonlinear dynamics during reflection of a plane internal wave at a sloping bottom. The effect of incoming wave amplitude is assessed by varying the incoming Froude number, Fr, and the effect of off-criticality is assessed by varying the slope angle in a range of near-critical values. At low Fr, the numerical results agree well with linear inviscid theory of near-critical internal wave reflection. With increasing Fr, the reflection process becomes nonlinear with the formation of higher harmonics and the initiation of fine-scale turbulence during the evolution of the reflected wave. Later in time, the wave respons..