Hydrodynamic regimes in offshore wind farms

Abstract

Análisis de los dominios hidrodinámicos y sus efectos en las fuerzas de inercia y arrastre en pilotes y de difracción en estructuras de gravedad tipo monolitos.
Offshore wind power has sharply increased its presence in the last few decades. This expansion has derived in much
bigger structures to be placed on the seabed; however, no revision about hydrodynamic regimes that should be taken
into account during the design of these facilities has been carried out. The equations developed by Morison et al. in
1950 to estimate the wave loads are commonly assumed as valid within professional and scientific activity, and no
revision of their investigation has been carried out since then. The formulation developed 65 years ago may not be
reliable enough to accurately predict the phenomena, since they were established for smaller bodies. This paper
analyses the available data from several European offshore wind farms in order to determine their hydrodynamic
domain and nature of forces that structures bear. The analysis has been performed with the aim of establishing the
relationship between inertia and drag forces acting on piles under wave loading conditions. Different criteria from
main standards within the sphere of maritime works have been followed for the analysis. Results clearly show how
inertia dominates in most cases and, consequently, the acceleration of fluid particle motion is a critical variable for
predicting coastal phenomena. In this sense, this research remarks the importance of that mathematical expressions
incorporate this fact, both for structural calculation and coastal process prediction and they should be reviewed in
future research studies.