A Linearized Analytical Model of Wave Attenuation by Cultivated Seaweeds

About

A python implementation of the analytical framework addressing the attenuation of both regular and irregular waves propagating over floating seaweed farms.

Theory

Kelp blades suspended on the longlines are modelled, as a first approximation, as rigid bars rotating around their upper ends. Assuming small-amplitude blade motions under low to moderate sea conditions, the frequency transfer function of the rotations can be obtained, with quadratic drag loads linearized. Subsequently, the hydrodynamic problem with regular waves propagating over suspended seaweed canopies is formulated using the continuity equation and linearized momentum equations with additional source terms within the vegetation region. Analytical solutions are obtained for the regular waves with their heights decaying exponentially as they propagate over the canopy. These analytical solutions are utilized as the basis to predict the wave attenuation of irregular waves while stochastic linearization of the quadratic drag loads is employed. Reduced velocity inside the canopy is utilized instead of velocity profiles following the linear wave theory as used in other energy-conservation-based models.

Inputs & outputs

Users should provide information regarding the waves (water depth, wave period, wave height for regular waves, and wave spectra of irregular waves) and the canopy (dimensions, density, and other properties). The code gives wave attenuation predictions, as well as velocity profiles and phase lag. Follow the provided example scripts.

GitLab

The code is developed openly at DTU GitLab Repository - WaveAttenuationBySeaweed where you can access the latest version. Future releases will be autuomatically imported.