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Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations

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A NACA 0018 airfoil in freestream velocity is oscillated in longitudinal, transverse, and angle-of-attack directions with respect to the freestream velocity, known as surge, plunge, and pitch. The lift-based equivalence method introduces phase shifts between these three motions to construct in-phase sinusoidal components for maximum lift, waveform construction. Lift cancellation is also determined with the exact negative pitch and plunge motion amplitudes found from the equivalence method to achieve out-of-phase wave destruction. Lift cancellation occurs when a combination of these motions is sought to obtain a constant lift magnitude throughout the oscillation cycle. To achieve both equivalence and cancellation of lift, a prescribed pure pitch amplitude through the Theodorsen theory equates the corresponding equivalent plunge amplitude and pitch-plunge phase shift. These Theodorsen, linear superposition findings of pitch-plunge are leveraged toward the Greenberg theory to determine a closed-form, surge-pitch-plunge solution through the addition of a surge-plunge phase shift and optimal surge amplitude for lift cancellation. The lift cancellation surge-pitch-plunge amplitudes define the equivalence amplitude investigated here and theoretically limit the experiment to combinations of the first lift harmonic of the Greenberg theory. The analytical results are then compared with experimental lift force measurements and dye visualization. The normalized lift differences due to unsteady wake and boundary-layer behavior are examined to explore the extents of the Greenberg theory for these cases of lift-based equivalence and cancellation.

Citation Formats

TY - DATA AB - A NACA 0018 airfoil in freestream velocity is oscillated in longitudinal, transverse, and angle-of-attack directions with respect to the freestream velocity, known as surge, plunge, and pitch. The lift-based equivalence method introduces phase shifts between these three motions to construct in-phase sinusoidal components for maximum lift, waveform construction. Lift cancellation is also determined with the exact negative pitch and plunge motion amplitudes found from the equivalence method to achieve out-of-phase wave destruction. Lift cancellation occurs when a combination of these motions is sought to obtain a constant lift magnitude throughout the oscillation cycle. To achieve both equivalence and cancellation of lift, a prescribed pure pitch amplitude through the Theodorsen theory equates the corresponding equivalent plunge amplitude and pitch-plunge phase shift. These Theodorsen, linear superposition findings of pitch-plunge are leveraged toward the Greenberg theory to determine a closed-form, surge-pitch-plunge solution through the addition of a surge-plunge phase shift and optimal surge amplitude for lift cancellation. The lift cancellation surge-pitch-plunge amplitudes define the equivalence amplitude investigated here and theoretically limit the experiment to combinations of the first lift harmonic of the Greenberg theory. The analytical results are then compared with experimental lift force measurements and dye visualization. The normalized lift differences due to unsteady wake and boundary-layer behavior are examined to explore the extents of the Greenberg theory for these cases of lift-based equivalence and cancellation. AU - Elfering, Kelsey A2 - Granlund, Kenneth DB - Open Energy Data Initiative (OEDI) DP - Open EI | National Renewable Energy Laboratory DO - KW - MHK KW - Marine KW - Hydrokinetic KW - energy KW - power KW - foil theory KW - NACA 0018 KW - surge KW - pitch KW - plunge KW - oscillation KW - airfoil KW - pitch-plunge KW - surge-plunge KW - surge-pitch-plunge KW - Theodersen KW - Greenberg KW - lift KW - phase shift KW - equivalence KW - cancellation KW - lift-based KW - NACA KW - 0012 KW - 0018 KW - Quasi-Steady KW - normalized lift KW - water tunnel KW - experiment KW - test KW - experimental KW - lab test KW - dye visualization KW - leading-edge vortex KW - LEV LA - English DA - 2020/01/01 PY - 2020 PB - North Carolina State University T1 - Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations UR - https://data.openei.org/submissions/7988 ER -
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Elfering, Kelsey, and Kenneth Granlund. Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations. North Carolina State University, 1 January, 2020, MHKDR. https://mhkdr.openei.org/submissions/348.
Elfering, K., & Granlund, K. (2020). Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations. [Data set]. MHKDR. North Carolina State University. https://mhkdr.openei.org/submissions/348
Elfering, Kelsey and Kenneth Granlund. Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations. North Carolina State University, January, 1, 2020. Distributed by MHKDR. https://mhkdr.openei.org/submissions/348
@misc{OEDI_Dataset_7988, title = {Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations}, author = {Elfering, Kelsey and Granlund, Kenneth}, abstractNote = {A NACA 0018 airfoil in freestream velocity is oscillated in longitudinal, transverse, and angle-of-attack directions with respect to the freestream velocity, known as surge, plunge, and pitch. The lift-based equivalence method introduces phase shifts between these three motions to construct in-phase sinusoidal components for maximum lift, waveform construction. Lift cancellation is also determined with the exact negative pitch and plunge motion amplitudes found from the equivalence method to achieve out-of-phase wave destruction. Lift cancellation occurs when a combination of these motions is sought to obtain a constant lift magnitude throughout the oscillation cycle. To achieve both equivalence and cancellation of lift, a prescribed pure pitch amplitude through the Theodorsen theory equates the corresponding equivalent plunge amplitude and pitch-plunge phase shift. These Theodorsen, linear superposition findings of pitch-plunge are leveraged toward the Greenberg theory to determine a closed-form, surge-pitch-plunge solution through the addition of a surge-plunge phase shift and optimal surge amplitude for lift cancellation. The lift cancellation surge-pitch-plunge amplitudes define the equivalence amplitude investigated here and theoretically limit the experiment to combinations of the first lift harmonic of the Greenberg theory. The analytical results are then compared with experimental lift force measurements and dye visualization. The normalized lift differences due to unsteady wake and boundary-layer behavior are examined to explore the extents of the Greenberg theory for these cases of lift-based equivalence and cancellation.}, url = {https://mhkdr.openei.org/submissions/348}, year = {2020}, howpublished = {MHKDR, North Carolina State University, https://mhkdr.openei.org/submissions/348}, note = {Accessed: 2025-05-04} }

Details

Data from Jan 1, 2020

Last updated Jan 14, 2021

Submitted Dec 4, 2020

Organization

North Carolina State University

Contact

Chris Vermillion

919.515.5244

Authors

Kelsey Elfering

North Carolina State University

Kenneth Granlund

North Carolina State University

DOE Project Details

Project Name Device Design and Robust Periodic Motion Control of an Ocean Kite System for Marine Hydrokinetic Energy Harvesting

Project Lead Carrie Noonan

Project Number EE0008635

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