Laboratory Experiments on the Interaction between Internal Waves and Floating Canopies

The interaction between internal solitary waves (ISWs) and floating canopies is studied experimentally using a jet-array wavemaker. The ISWs are generated by forcing a prescribed vertical distribution of mass flux based on the extended Korteweg-de Vries (eKdV) solution. Twelve experimental cases are studied, encompassing three ISWs profiles, two roughness densities for the 3D-printed floating canopy, and two canopy lengths. Phase speeds and wave profiles are captured via planar laser-induced fluorescence and the velocity field is measured using particle imaging velocimetry. Measured wave profiles are directly compared with the eKdV predictions across multiple locations to assess the effect of the floating canopy. The presence of the canopy leads to a region of flow adjustment. The redirection of the flow below the canopy leads to higher velocities in the upper layer compared to eKdV predictions. This does not trigger a significant increase in ISW amplitude. A slower jet emanates from the downstream end of the canopy and merges with the accelerated fluid. High-amplitude ISWs and longer canopy lengths can also trigger flow separation at the end of the canopy. These processes lead to an elongated trailing edge or a secondary plateau in the measured wave profiles.