Sensitivity Analysis to Control the Far-Wake Unsteadiness Behind Turbines

Esteban Ferrer, Oliver M.F. Browne and Eusebio Valero
Additional contact information
Esteban Ferrer: ETSIAE (School of Aeronautics)—Universidad Politécnica de Madrid, Pza Cardenal Cisneros 3, E-28040 Madrid, Spain
Oliver M.F. Browne: Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ 85721, USA
Eusebio Valero: ETSIAE (School of Aeronautics)—Universidad Politécnica de Madrid, Pza Cardenal Cisneros 3, E-28040 Madrid, Spain

Energies, 2017, vol. 10, issue 10, 1-21

Abstract: We explore the stability of wakes arising from 2D flow actuators based on linear momentum actuator disc theory. We use stability and sensitivity analysis (using adjoints) to show that the wake stability is controlled by the Reynolds number and the thrust force (or flow resistance) applied through the turbine. First, we report that decreasing the thrust force has a comparable stabilising effect to a decrease in Reynolds numbers (based on the turbine diameter). Second, a discrete sensitivity analysis identifies two regions for suitable placement of flow control forcing, one close to the turbines and one far downstream. Third, we show that adding a localised control force, in the regions identified by the sensitivity analysis, stabilises the wake. Particularly, locating the control forcing close to the turbines results in an enhanced stabilisation such that the wake remains steady for significantly higher Reynolds numbers or turbine thrusts. The analysis of the controlled flow fields confirms that modifying the velocity gradient close to the turbine is more efficient to stabilise the wake than controlling the wake far downstream. The analysis is performed for the first flow bifurcation (at low Reynolds numbers) which serves as a foundation of the stabilization technique but the control strategy is tested at higher Reynolds numbers in the final section of the paper, showing enhanced stability for a turbulent flow case.

Keywords: stability analysis; sensitivity analysis; wake unsteadiness; wake meandering; passive control; wind turbine; tidal turbine; discontinuous Galerkin (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2017
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

Downloads: (external link)
https://www.mdpi.com/1996-1073/10/10/1599/pdf (application/pdf)
https://www.mdpi.com/1996-1073/10/10/1599/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:10:y:2017:i:10:p:1599-:d:114890

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().