Model validation

WindFarmer Knowledge Centre Model validation

WindFarmer models are continually validated and to inform updates to the Wake, Blockage, Energy and other models. The papers, presentations, webinars and reports below are a useful selection from historical validations of the models within WindFarmer.

Title	Date	Event / type	Models	Notes
Boundary layer educated long range wake estimates from WindFarmer CFD.ML	Jun 2024	WindEurope Technical Workshop, Dublin - Presentation	Wakes; CFD.ML	The inclusion of atmospheric conditions in the CFD.ML model training has improved our capability to capture the long-range wakes.
Waking up to the magnitude of cluster and far-field wakes	Jun 2024	Wind Europe Technology Workshop 2024	DNV CFD, RWE CFD, RWE VV, WindFarmer EV+LWF	RWE-DNV collaboration looking effect on wind farm annual energy production from far-field wakes. Wind farm wakes detected in SCADA for distance of 30 km (250 RD) in both unstable and stable atmospheric conditions. Several models are compared to measured SCADA production at two wind farms, Amrumbank and Triton Knoll. Conclusions: * Cluster wake impact on energy yield is large on plateau of thrust curve. * Aggregated cluster effect (using synthetic FD): * 3% - 4% for Amrumbank, and * 2% to 4% for Triton Knoll. * Differences between model predicted aggregated losses are within the typical uncertainties used for turbine interaction losses, though there is a tendency for the models best agreeing with the SCADA data (CFD models) to predict larger losses than the engineering models.
CFD.ML – A new hope for rapid turbine interaction modelling?	Oct 2023	ACP Resource and Technology, Austin, Texas - Poster	Wakes; Blockage; CFD.ML	Poster introducing the CFD.ML turbine interaction model and latest validation.
Big cluster & far-field wakes - an assessment of multi-fidelity models against North Sea wind farms' SCADA data	Oct 2023	ACP Resource and Technology, Austin, Texas - Poster	Wakes; RANS CFD	The effect of cluster wakes is investigated for the object wind farms of Amrumbank West (ARB) and Triton Knoll (TK), operating in different parts of the North Sea. Joint RWE and DNV work. Investigation of DNV and RWE RANS CFD, WindFarmer Eddy Viscosity and RWE Viscous Vortex model performance.
AI for turbine interactions: testing the intelligence of CFD.ML	Jun 2023	WindEurope Technology Workshop, Lyon - Presentation	Wakes; Blockage; CFD.ML	An introduction to DNV's CFD.ML turbine interaction model. Validation of it's skill in predicting blockage, internal wakes and external wakes offshore. Patterns of front row production show the model captures blockage impacts well.
Blockage and cluster-to-cluster interactions from dual scanning lidar measurements	May 2023	WESC, Glasgow	RANS CFD, Wakes, Blockage	Collaboration between ENBW and DNV testing RANS CFD against direct measurements of cluster wakes and blockage from LIDAR wind speeds and also SCADA power measurements.
Far-distant offshore wakes: How far is too far and are we getting it right?	Jun 2022	Wind Europe Technology Workshop 2022	WindFarmer EV + LWF	Investigation on cluster wakes effects, for 4 operational projects in the North Sea, with neighbouring wind farms located between 120 and 300 rotor diameters (RD) upstream of the object wind farm. The study relied on EV + LWF correction, as implemented in WindFarmer-Analyst. The main conclusion from this early study was that the magnitude of the impact from cluster wakes at large distances was larger than captured by the model. This finding led to a retuning of the wake recovery settings in the LWF model, retuned configuration which DNV now uses (since July 2022), when calculating external losses from neighbouring wind farm.
Creating the next generation of validated turbine interaction models for offshore wind farms (Webinar)	Jun 2022	Webinar	Wakes; CFD.ML	Webinar describing the 2022 DNV validation of internal and external wakes for multiple DNV models. A justification for updated DNV Large Wind Farm Correction (LWF) settings used offshore to capture external wakes is shared. We present the internal wake effect validation described in the paper: T Levick et al 2022 J. Phys.: Conf. Ser. 2257 012010
Validating the next generation of turbine interaction models (paper)	Mar 2022	WindEurope Annual Event Bilbao - Paper	Wakes; CFD.ML	T Levick et al 2022 J. Phys.: Conf. Ser. 2257 012010. A validation framework for testing of the internal wake effects is applied to 6 offshore projects to compare performance of 4 DNV wake models: WindFarmer Eddy Viscosity + Large Wind Farm Correction (LWF); Modified Park + LWF; CFD.ML; Stratified Eddy Viscosity
Measuring and Modelling Wind Farm Blockage Offshore	Sep 2021	WindEurope Technology Workshop - Presentation	Blockage	Validation using upstream long-range lidar to test the wind speed profiles in collaboration with the European offshore developer EnBW. Results shows DNV's RANS CFD model replicates the wind profiles well when WRF is used to define for boundary conditions, supporting the magnitude of the DNV blockage correction.
Wind-Farm-Scale blockage	Feb 2020	WinterWind - presentation	Blockage, RANS CFD	Testing DNV's BEET blockage correction against RANS CFD at onshore wind farms. Comparisons of CFD to front row of wind farm profiles show that CFD captures blockage well. BEET predictions are compared to CFD for 12 onshore wind farms that were not included in the BEET training set. Explanation of important drivers for blockage: layout and wind rose are less important.
Blockage effects in WindFarmer: Analyst	Feb 2019	Webinar	Blockage	Rational behind the blockage effect and DNV's blockage correction models: BEET and RANS CFD. BEET is a surrogate for predictions of wind farm blockage predicted by DNV's high fidelity RANS CFD model. Discussion of the validation of BEET and how BEET may be used in WindFarmer.
Wind Farm Blockage and the Consequences of Neglecting Its Impact on Energy Production	Jun 2018	Paper	Blockage; RANS CFD	J Bleeg et al. Energies 2018, 11(6), 1609; https://doi.org/10.3390/en11061609 DNV's original paper with showing the magnitude of blockage effects, including validation of DNV's CFD model against measurements.
Improving confidence in wake predictions through operational validations	Jun 2017	WindEurope Offshore - presentation	Wakes	Patterns of production at onshore and offshore large wind farms presented and compared to WindFarmer Eddy Viscosity + LWF model. Investigation into LWF settings for onshore projects in different stability conditions support our +0.03 or +0.05 increased roughness adders.
WindFarmer white paper	Apr 2016	Report	Wakes, Blockage, Annual energy production	The basis for each WindFarmer energy and wake model component, demonstrated using comparisons to project data and case studies. Learn how WindFarmer's most advanced models (in 2016) provide you with the most accurate energy predictions.
WindFarmer Validation Report	Apr 2014	Report	Shadow Flicker, Wakes, Blockage, Annual energy production	A overview of the WindFarmer models and summaries of the validation efforts (circa 2014). The validation report includes a Shadow Flicker validation not included elsewhere: See page 17
Impact of Large Neighbouring Wind Farms on Energy Yield of Offshore Wind Farms	Nov 2011	EWEA Offshore Conference, Amsterdam - Paper	Wakes	The WindFarmer large wind farm correction methodology is explained, including the recovery profile, with validation against offshore wind farms.
New Developments in Wake Models for Large Wind Farms	May 2009	Paper	Wakes	Onshore large wind farm model and validation. The original evidence supporting the application of the WindFarmer LWF model onshore, including our application of the increased roughness = Base roughness + 0.03 input for onshore sites.