Experimental investigation of nonlinear internal waves in deep water with miscible fluids

We report the first experimental evidence of nonlinear Internal Solitary Waves in deep water and for miscible fluids. The results consisting of amplitude, speed, and wavelength are validated against experiments and direct numerical simulations where the effect of the diffused interface is taken into account. The waves are generated by means of a dam break and their evolution is recorded with Laser Induced Fluorescence and Particle Image Velocimetry. In particular, data collected in a frame moving with the waves are presented here for the first time. Our results are representative of geophysical applications in the deep ocean where weakly nonlinear theories fail to capture the characteristics of large amplitude ISWs from field observations.