Impact of Wind Veer and the Coriolis Force for an Idealized Farm to Farm Interaction Case

Abstract

The impact of the Coriolis force on the long distance wake behind wind farms is investigated using Large Eddy Simulations (LES) combined with a Forced Boundary Layer (FBL) technique. When using the FBL technique any mean wind shear and turbulent fluctuations can be added with body forces. The wind shear can also include the mean wind veer due to the Coriolis force. The variation of the Coriolis force due to local deviations from the mean profile, e.g., from wakes, is not taken into account in the FBL. This can be corrected for with an extra source term in the equations, hereon defined as the Coriolis correction. For a row of 4 turbines it is shown that the inclusion of the wind veer turns the wake to the right, while including the Coriolis correction turns it to the left. When including both wind veer and Coriolis correction the impact of wind veer dominates. For an idealized farm to farm interaction case, two farms of 4 ∗ 4 turbines with 6 km in between, it can be seen that when including wind veer and the Coriolis correction a approximately 3% increase in the relative production for a full wake direction can be seen and only a slightly smaller increase can be seen when including only wind veer. The results indicate that FBL can be used for studies of long distance wakes without including a Coriolis correction but efforts need to be taken to use a wind shear with a correct mean wind veer.

Investigation of Marine Wind Veer Characteristics Using Wind Lidar Measurements

“…Similar conclusions were also obtained by Bardal et al [49], who found a reduced power output in the whole partial load regime under high veer conditions. In contrast, Eriksson et al [50] examined the effect of wind veer and the Coriolis force on an idealized farm-to-farm interaction case, in which the estimated power production was found to increase with the inclusion of the wind veer effect. Murphy et al [51] concluded that the influence of wind veer on turbine power production is strongly tied with wind speed, in which a large wind veer angle generally results in power gains at a wind speed exceeding 10 m/s.…”

Influence of the geostrophic wind direction on the atmospheric boundary layer flow

“…Individual wind turbines create wakes which have a streamwise length scale which is an order or magnitude larger than the turbine diameter (Chamorro & Porté-Agel 2009); Platis et al (2018) have reported wind farm wakes of the order of tens of kilometres in length. Since Coriolis forces influence flow structures on large length scales and affect vertical transport, a thorough understanding of their impact has become increasingly important in the design and operation of large wind farms van der Laan & Sørensen 2017;Eriksson et al 2019;Gadde & Stevens 2019). All previous studies of the influence of Coriolis forces in wind farm simulations have neglected the horizontal component of Earth's rotation and the sensitivity of phenomena such as the vertical entrainment of kinetic energy above large wind farms to the direction of the geostrophic velocity have not been examined (see e.g.…”

Effect of Coriolis Force on Vibration of Annulus Pipe

“…The results for the void tube with no velocity are described solving Equation (11) imposing ρ = 0, v = 0 and m = m 2 . The frequencies are: Finally, Figure 6 shows the curves of critical frequencies ω with respect to the fluid velocity v for the first quadrant of the graph.…”

“…Helped by the experiments described in [9,10] it was possible to assume that the contribution of both the Coriolis force and the centrifugal force lead to flutter effects that can be dangerous for the strength of the structure. In [11], Eriksson et al investigated the impact of the Coriolis force on the long distance wake behind wind farms by using Large Eddy Simulations (LES) combined with a Forced Boundary Layer (FBL) technique. The results indicate that FBL can be used for studies of long distance wakes without including a Coriolis correction, but efforts need to be taken to use a wind shear with a correct mean wind veer.…”