Laboratory investigation of turbulent dissipation in an internal solitary wave breaking over a submerged Gaussian ridge

Abstract

Laboratory experiments were conducted to investigate an internal solitary wave breaking over a submerged Gaussian ridge. Particle image velocimetry (PIV) was performed with a high-speed camera to analyze the macro- and microstructures of wave-breaking evolution and subsequent induced turbulence and mixing. Four types of wave breaking, namely, plunging breaking, collapsing breaking, plunging-collapsing breaking, and surging breaking, were identified, along with their different evolutionary processes and breaking mechanisms. The turbulent dissipation rates estimated from the PIV results were on the order of 10−6 to 10−4 m2/s3 during the breaking, with the smallest values in the plunging breaking and the largest in surging breaking. Generally, the intensity of turbulence in plunging breakers seems to be insensitive to the changing wave slope; however, the surging breaker shows an opposite trend.