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Westergaard, Carsten

Publications and source records attributed to Westergaard, Carsten.

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Accelerated Wind-Turbine Wake Recovery Through Actuation of the Tip-Vortex Instability

Advances in wind-plant control have often focused on more effectively balancing power between neighboring turbines. Wake steering is one such method that provides control-based improvements in a quasi-static way, but this does little to fundamentally change the wake recovery process, and thus, it has limited potential. This study investigates use of another control paradigm known as dynamic wake control (DWC) to excite the mutual inductance instability between adjacent tip-vortex structures, thereby accelerating the breakdown of the structures. The current work carries this approach beyond the hypothetical by applying the excitation via turbine control vectors that already exist on all modern wind turbines: blade pitch and rotor speed control. The investigation leverages a free-vortex wake method (FVWM) that allows a thorough exploration of relevant frequencies and amplitudes of harmonic forcing for each control vector (as well as the phase difference between the vectors for a tandem configuration) while still capturing the essential tip-vortex dynamics. The FVWM output feeds into a Fourier stability analysis working to pinpoint candidate DWC strategies suggesting fastest wake recovery. Near-wake length reductions of >80% are demonstrated, although without considering inflow turbulence. Analysis is provided to interpret these predictions considering the presence of turbulence in a real atmospheric inflow.

17 WIND ENERGY↗
DOE OSTI2016

Pentalum SpiDAR Deployment at SWiFT FY17.

The Texas Tech University ( TTU ) research group is actively studying the wake development of wind turbines, as part of developing innovative wake control strategies to improve the performance of wind farms. Recently, the team received a set of five new gro und lidars to perform field measurements at the Sandia National Laboratories SWiFT site. This document describes tests details including configurations, timeframe, hardware, and the required collaboration from the Sandia team. This test plan will facili tate the coordination between both TTU and the Sandia team in terms of site accessibility, staff training, and data sharing to meet the specific objectives of the tests.

17 WIND ENERGY↗
DOE OSTI2016

Continuous Reliability Enhancement for Wind (CREW). Program Update

Sandia's Continuous Reliability Enhancement for Wind (CREW) Program is a follow on project to the Wind Plant Reliability Database and Analysis Program. The goal of CREW is to characterize the reliability performance of the US fleet to serve as a basis for improved reliability and increased availability of turbines. This document states the objectives of CREW and describes how data collected for CREW will be used in analysis. A critical aspect to the success of the CREW project is data input from participating owner/operators. The level of detail and the quality of input data provided dictates the type of analysis that can be accomplished. Options for analysis range from high level availability summaries to detailed analysis of failure modes for individual equipment items. Specific types of input data are identified followed by samples of the type of output that can be expected along with a discussion of benefits to the user community.

17 WIND ENERGY↗