A zone of deceleration upwind of the cliff and the downwind acceleration zone are maintained with flow ±25º to the perpendicular. As the angle of attack from perpendicular increases i.e. flow becomes more parallel to the coast, both upwind and downwind zones become incoherent in wind speeds and turbulence intensity.
Wind turbines are often located on coastal cliffs to maximize the benefit of the speed-up and to experience higher wind speeds when flow is from offshore. However, little is known about higher moments of the flow and the magnitude of these effects that are sub-grid scale in most models but are of key importance to wind turbine siting.
Flow close to a cliff is explored using observations and CFD simulations to quantify flow characteristics at scales not currently resolved by most atmospheric models.