Study of Atmospheric Boundary Layer Flows over a Coastal Cliff

Abstract

The extent to which a wind energy site is affected by a coastal cliff is presented by studying numerically a neutral Atmospheric Boundary Layer (ABL) flow using an RNG k-ε model and different geometries. Initially, the classical flow over a forward-facing step is modelled, followed by the modelling of a neutral ABL over a rough plane in two and three dimensions with various types of ground conditions. Finally, the two and three-dimensional flows over a forward-facing step, representing a coastal cliff, in a neutral ABL were modelled and applied to the Atlantic Wind Test Site (AWTS), site composed of a wind turbine testing facility and a 13 MW wind farm, in the province of Prince Edward Island, Canada. After assessing that the model can predict classical flows and ABL with relatively good accuracy and robustness, the results show that the extent of the effect of a coastal cliff on the flow above the AWTS is limited to a distance of 5h downstream of the (height h = 10 m) cliff. Based on the sitting of the existing wind power infrastructure, it appears that the coastal cliff does not influence the power capacity of the site.

Keywords

Computational wind engineering atmospheric boundary layer forward-facing step coastal cliff roughness height full size comparisons

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