Blocking effects on mean ocean currents by offshore wind farm foundations

Development of offshore wind farms in shallow coastal seas is becoming increasingly widespread, and raises questions as to the potential extent of hydrodynamic impacts to the oceanic environment. This work presents an idealized analytical model to study the potential alterations to the mean ocean currents due to the presence of the offshore wind farm foundation structures and their increased friction. We find that this ``blocking'' of ocean currents has a simple scaling that depends primarily on the ratio of the friction inside and outside the farms, and depending on the farm characteristics can either be negligible, or change mean currents by around 10% in existing farms in the North Sea.