Interaction between Internal Solitary Waves and Floating Canopies

Submerged canopies are known to generate a shear layer at the canopy-flow interface, which drives canopy-scale vortices and enhances momentum dissipation. The interaction between internal solitary waves (ISWs) and floating canopies results in a complex nonlinear coupling between the shear layers induced by ISWs at the pycnocline and at the canopy interface. ISW-canopy dynamics are studied both experimentally and numerically. The ISWs are generated under a fixed ratio of lower layer depth ($h_2$) to upper layer depth ($h_1$) of $h_2/h_1 = 4.5$ with varying amplitudes of $a/h_1 = \{-0.5, -0.75, -1\}$. The canopy length and porosity vary across four configurations, with $l_c/h_1 = \{5, 10\}$, and porosity $n = \{0.648, 0.964\}$. A synchronized system of Planar Laser-induced Fluorescence and Particle Imaging Velocimetry is employed to capture the wave profile and velocity field around the canopy. Experimental measurements are used to verify complementary RANS simulations of enhanced spatial resolution and an extended observation domain. For the transitional canopy with porosity $ n = 0.964$, the canopy structure primarily behaves as a weakly dissipative zone, resulting in an amplitude reduction of approximately 5\%. For the dense canopy with $n = 0.648$, the opposing shear layers beneath the canopy and at the pycnocline interact to form a vortex-induced jet that deforms the ISW structure. Downstream of the canopy, a vortex-driven wave steepening process is initiated by flow separation and the opposing shear at the pycnocline, leading to an amplitude growth of approximately 10\%.