Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations
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 -
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
Original Source
https://mhkdr.openei.org/submissions/348Research Areas
Keywords
MHK, Marine, Hydrokinetic, energy, power, foil theory, NACA 0018, surge, pitch, plunge, oscillation, airfoil, pitch-plunge, surge-plunge, surge-pitch-plunge, Theodersen, Greenberg, lift, phase shift, equivalence, cancellation, lift-based, NACA, 0012, 0018, Quasi-Steady, normalized lift, water tunnel, experiment, test, experimental, lab test, dye visualization, leading-edge vortex, LEVDOE 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