FIELD VALIDATION FOR A HYDRODYNAMIC FINITE ELEMENT MODEL OF A MACROALGAE LONGLINE AT AN EXPOSED SITE

Successful design and operation of a macroalgae farm depends on an accurate understanding of the system's behavior in waves and currents. Dynamic finite element modeling techniques can be used to quantify the response of aquaculture farms to operational and extreme environmental conditions. In this study, a dynamic finite element model of an exposed kelp line was developed in Hydro-FE. This model used previously measured mechanical properties of Saccharina latissima. It also employed hydrodynamic properties previously derived from tank tests of a physical model of a 1-m section of a kelp longline with 3-m long kelp fronds, including normal and tangential drag coefficients and added mass coefficients. The project team deployed load-cells on each mooring leg of the exposed kelp line to measure mooring tensions under environmental loading.  The environmental conditions, including waves, currents, and tidal elevation were measured with two Acoustic Wave and Current (AWAC) sensors each deployed near the load cells.  These loadcases were replicated in the dynamic finite element model. Power-spectral densities and maximum values for mooring line tension were calculated for the field data and the model outputs for the same environmental forcing conditions. Root-mean-squared error was quantified between the model predictions and the field observations.