Actuator disc modelling of wake interaction in Horns Rev wind farm
(English)In: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Article in journal (Other academic) Submitted
Large eddy simulations of the Navier-Stokes equations are performed tosimulate the Horns Rev off shore wind farm 15 km outside the Danish westcoast. The aim is to achieve a better understanding of the wake interactioninside the farm. The simulations are performed by combining the in-housedeveloped computer code EllipSys3D with the actuator-disc methodology. Inthe actuator-disc method the blades are represented by a disc at which bodyforces representing the aerodynamic loading are introduced. The body forcesare determined by computing local angles of attack and tabulated aerofoil coefficients.The advantage of using the actuator-disc technique is that it is notnecessary to resolve blade boundary layers since the computational resourcesare devoted to simulating the dynamics of the flow structures.In the present study approximately 13.6 million mesh points are used toresolve the wake structure in the park. The park contains 80 wind turbinesdistributed over an area of about 20km2. Since it is not possible to simulate allturbines, the 2 central columns of turbines have been simulated with periodicboundary conditions. This corresponds to an infinitely wide farm with 10turbines in downstream direction. Simulations were performed within plusminus 15 degrees of the turbine alignment, making the wide farm approximationreasonable.The results from the CFD simulations are evaluated and the downstreamevolution of the velocity field is depicted. Special interest is given to whatextent the production is dependent on the inflow angle and turbulence level.The study shows that the applied method captures the main productionvariation within the wind farm. The result further demonstrates that levelsof production correlate well with measurements. However, in some cases thevariation of the measurement data is caused by variation of measurement conditionswith inflow angles.
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-9913OAI: oai:DiVA.org:kth-9913DiVA: diva2:158175
QS 201203272009-01-302009-01-302012-03-27Bibliographically approved