An Advanced Actuator Line Method for Wind Energy Applications and Beyond: Preprint
Abstract
The actuator line method to represent rotor aerodynamics within computational fluid dynamics has been in use for over a decade. This method applies a body force to the flow field along rotating lines corresponding to the individual rotor blades and employs tabular airfoil data to compute the force distribution. The actuator line method is attractive because compared to bladeresolved simulations, the required mesh is much simpler and the computational cost is lower. This work proposes a higher fidelity variant of the actuator line method meant to fill the space between current actuator line and bladeresolved simulations. It contains modifications in two key areas. The first is that of freestream velocity vector estimation along the line, which is necessary to compute the lift and drag along the line using tabular airfoil data. Most current methods rely on point sampling in which the location of sampling is ambiguous. Here we test a velocity sampling method that uses a properly weighted integral over space, removing this ambiguity. The second area of improvement is the function used to project the onedimensional actuator line force onto the threedimensional fluid mesh as a body force. We propose and test a projection function that spreads the forcemore »
 Authors:
 Publication Date:
 Research Org.:
 National Renewable Energy Lab. (NREL), Golden, CO (United States)
 Sponsoring Org.:
 USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE4W)
 OSTI Identifier:
 1349215
 Report Number(s):
 NREL/CP500067611
 DOE Contract Number:
 AC3608GO28308
 Resource Type:
 Conference
 Resource Relation:
 Conference: Presented at the American Institute of Aeronautics and Astronautics SciTech 2017, 913 January 2017, Grapevine, Texas
 Country of Publication:
 United States
 Language:
 English
 Subject:
 17 WIND ENERGY; actuator line; wind turbine; aerodynamics; computational fluid mechanics
Citation Formats
Churchfield, Matthew, Schreck, Scott, MartinezTossas, Luis A., Meneveau, Charles, and Spalart, Philippe R. An Advanced Actuator Line Method for Wind Energy Applications and Beyond: Preprint. United States: N. p., 2017.
Web. doi:10.2514/6.20171998.
Churchfield, Matthew, Schreck, Scott, MartinezTossas, Luis A., Meneveau, Charles, & Spalart, Philippe R. An Advanced Actuator Line Method for Wind Energy Applications and Beyond: Preprint. United States. doi:10.2514/6.20171998.
Churchfield, Matthew, Schreck, Scott, MartinezTossas, Luis A., Meneveau, Charles, and Spalart, Philippe R. Fri .
"An Advanced Actuator Line Method for Wind Energy Applications and Beyond: Preprint". United States.
doi:10.2514/6.20171998. https://www.osti.gov/servlets/purl/1349215.
@article{osti_1349215,
title = {An Advanced Actuator Line Method for Wind Energy Applications and Beyond: Preprint},
author = {Churchfield, Matthew and Schreck, Scott and MartinezTossas, Luis A. and Meneveau, Charles and Spalart, Philippe R.},
abstractNote = {The actuator line method to represent rotor aerodynamics within computational fluid dynamics has been in use for over a decade. This method applies a body force to the flow field along rotating lines corresponding to the individual rotor blades and employs tabular airfoil data to compute the force distribution. The actuator line method is attractive because compared to bladeresolved simulations, the required mesh is much simpler and the computational cost is lower. This work proposes a higher fidelity variant of the actuator line method meant to fill the space between current actuator line and bladeresolved simulations. It contains modifications in two key areas. The first is that of freestream velocity vector estimation along the line, which is necessary to compute the lift and drag along the line using tabular airfoil data. Most current methods rely on point sampling in which the location of sampling is ambiguous. Here we test a velocity sampling method that uses a properly weighted integral over space, removing this ambiguity. The second area of improvement is the function used to project the onedimensional actuator line force onto the threedimensional fluid mesh as a body force. We propose and test a projection function that spreads the force over a region that looks something like a real blade with the hope that it will produce the blade local and near wake flow features with more accuracy and higher fidelity. Our goal is that between these two improvements, not only will the flow field predictions be enhanced, but also the spanwise loading will be made more accurate. We refer to this combination of improvements as the advanced actuator line method. We apply these improvements to two different wind turbine cases. Although there is a strong wind energy motivation in our work, there is no reason these advanced actuator line ideas cannot be used in other applications, such as helicopter rotors.},
doi = {10.2514/6.20171998},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 24 00:00:00 EDT 2017},
month = {Fri Mar 24 00:00:00 EDT 2017}
}

The actuator line method to represent rotor aerodynamics within computational fluid dynamics has been in use for over a decade. This method applies a body force to the flow field along rotating lines corresponding to the individual rotor blades and employs tabular airfoil data to compute the force distribution. The actuator line method is attractive because compared to bladeresolved simulations, the required mesh is much simpler and the computational cost is lower. This work proposes a higher fidelity variant of the actuator line method meant to fill the space between current actuator line and bladeresolved simulations. It contains modifications inmore »

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