## What is/are Actuator Line?

Actuator Line - This study focuses on developing and applying an actuator line model (ALM) to predict the wake behind floating offshore wind turbines (FOWTs).^{[1]}The simulations are conducted using the actuator line model (ALM) coupled with a three-dimensional Navier Stokes solver implementing the k−ω shear stress transport turbulence model.

^{[2]}The turbines are taken into account using FAST (from NREL) and their effects are imposed into the fluid domain through an actuator line model (ALM) for which specific enhancements are proposed.

^{[3]}The Actuator Line Method (ALM), combining a lumped-parameter representation of the rotating blades with the CFD resolution of the turbine flow field, stands out among the modern simulation methods for wind turbines as probably the most interesting compromise between accuracy and computational cost.

^{[4]}In the present study, an actuator line model code was implemented in the OpenFOAM flow solver.

^{[5]}Recently, actuator line model become popular in studying wind-turbine wakes.

^{[6]}To understand the effects produced by different approaches, we carry out simulations using a coherent-structure resolving turbulence model, for which we test three actuator representations: Actuator Disk, Blade-Element Momentum, and Actuator Lines.

^{[7]}Analysis tools with a fidelity higher than the ubiquitous Blade Element Momentum (BEM) method are needed by now in wind energy; in particular, different research groups have recently proposed the application of the Actuator Line Method (ALM) to wind turbines, to exploit the benefits of an accurate discretization of the wake through Computational Fluid Dynamics and the computational cost saving associated to the lumped parameter modeling of the blade.

^{[8]}Firstly, the wind turbine control algorithms including torque, pitch and yaw controls are implemented in LES with Actuator Line Model (ALM).

^{[9]}The effect of two pitch parameters (the fold angle and the incline angle) on the instantaneous aerodynamic forces and overall performance of a straight-bladed VAWT under a tip-speed ratio of 4 is investigated using an actuator line model, achieved in ANSYS Fluent software and validated by previous experimental results.

^{[10]}Among them, the Actuator Line Method (ALM) stands out in terms of accuracy and computational cost.

^{[11]}Turbulent flow fields behind wind turbines are investigated using LES and Actuator Line Model with OpenFOAM on locally clustered Cartesian grids in a parallel computing environment.

^{[12]}The purpose of this paper is to implement a CFD-based Computationally-Efficient approach based on an actuator line model (ALM) for FOWTs aerodynamics.

^{[13]}ROAM is Cartesian-based, employing an actuator line model for the rotor and an immersed boundary model for the fuselage.

^{[14]}And an Actuator Line Model supplies the CFD tool with body forces that mimic the impact of moving objects on the airflow, thus, avoiding computationally expensive dynamic meshing.

^{[15]}Actuator disc and actuator line techniques are widely used for modelling wind turbines operating in wind farms.

^{[16]}To simulate this interdependence, the actuator line method (ALM) has been implemented in the atmospheric code Meso-NH, which is an LES research code developed by the French weather services.

^{[17]}In our simulations, the wind turbine blades are modeled as actuator lines in the incompressible Navier–Stokes equations.

^{[18]}In the present study, the effects of the actuator line force smearing on the predicted near-wake development of a model wind turbine are evaluated.

^{[19]}The actuator line model is used to predict the aerodynamic performance of wind turbine.

^{[20]}The turbine is taken into account using FAST (from NREL) and its effects are imposed into the fluid domain through an actuator line model.

^{[21]}In this fundamental study the cumulant LBM is scrutinised for actuator line simulations of wind turbines.

^{[22]}In the present work, the near-wake generated for a vertical axis wind turbine (VAWT) was simulated using an actuator line model (ALM) in order to validate and evaluate its accuracy.

^{[23]}The actuator line is a lifting line representation of aerodynamic surfaces in computational fluid dynamics applications but with non-singular forces, which reduces the self-induced velocities at the line.

^{[24]}The force smearing in the actuator line technique ensures its numerical stability, but also breaks its intended similarity to the lifting line by similarly smearing its vorticity in the flow domain.

^{[25]}The actuator line (AL) was intended as a lifting line (LL) technique for computational fluid dynamics (CFD) applications.

^{[26]}The turbine is represented using an actuator line model in a pseudo-spectral method-based solver.

^{[27]}The wind turbine is represented by the actuator line model (ALM).

^{[28]}The numerical simulations adopt both the actuator line method and the full rotor geometry method.

^{[29]}The subgrid model for the flow across the chordae tendineae is based on the Actuator Line Method, which means that they are represented by drag coefficients.

^{[30]}This study focuses on the coupled aeroelastic wake behavior of the wind turbine and developed a new tool called ALFBM, which combines the Actuator Line Method (ALM) and the nonlinear finite element Beam theory.

^{[31]}The OpenFOAM package incorporated with actuator line method (ALM) is employed to calculate the aerodynamic characteristics of large wind turbines in an offshore wind farm.

^{[32]}The ASM appears to overcome the inadequacy of actuator line models to account for the flow blockage of the rotor blades when they are on the up-stream side of the revolution, because the ASM uses a surface instead of a line to represent the blade.

^{[33]}Rotors representation were introduced into computational domain by means of Actuator Line Model.

^{[34]}Second, a reference turbine in surging motion is studied using an actuator line OpenFOAM model as reference and an actuator cylinder model (with and without dynamic inflow model).

^{[35]}The actuator line (AL) model instead of the geometry-resolved method is adopted to represent the rotor.

^{[36]}

## large eddy simulation

We perform large-eddy simulations (LES) with actuator line modeling of a turbine operating in a moderately stable boundary layer in the presence of LLJs.^{[1]}We then perform large-eddy simulation (LES) of open-channel flow for 28 layouts of tidal turbines using an actuator line method with doubly periodic boundary conditions.

^{[2]}To further improve the numerical accuracy of the turbine wake dynamics under atmosphere turbulence, this work proposes some improvements to the actuator line-large-eddy simulation (AL-LES) method.

^{[3]}Large eddy simulations and an adaption of the actuator line method (in order to describe arbitrary paths) are used to study the turbulent flow with and without Deep Green for a specific site.

^{[4]}A hybrid Large Eddy Simulation (LES) / Actuator Line Model (ALM) computational approach is employed to simulate the turbulent wake of a two-bladed rotor in hover.

^{[5]}In this work, the mean flow streamtube around a single DTU 10MW wind turbine, under yaw misalignement and turbulent inflow is investigated with Large-Eddy Simulation combined to the Actuator Line method.

^{[6]}Actuator Line Model (ALM) combined with Large Eddy Simulation (LES) is a promising way to comprehend this phenomenon.

^{[7]}In this work the results of a validated numerical method, based on a Large Eddy Simulation-Actuator Line Model framework, was applied to simulate a real 7.

^{[8]}In this study, we analyze the near-wake characteristics of a 5-MW single wind turbine using a large-eddy simulation with the actuator line method.

^{[9]}A large-eddy simulation-actuator line method (LES-ALM) applied to a single horizontal axis tidal turbine is presented and validated against experimental data.

^{[10]}In this study, a neutral atmospheric boundary layer and wind turbine blades were constructed in a large eddy simulation and actuator line model for conducting a field experiment of a wind turbine.

^{[11]}High-fidelity approaches such as large eddy simulations (LES) with the actuator line (AL) model which predicts detailed wake structures, fail to be applied in wind farm engineering applications due to its expensive cost.

^{[12]}A large eddy simulation and an actuator line model are introduced in the present work to simulate the wake field and aerodynamic loads of wind turbines with different longitudinal spacings.

^{[13]}To extend the knowledge about turbine-to-turbine interplay in tidal arrays, high-fidelity numerical simulations using a Large-Eddy Simulation-Actuator Line Method (LES-ALM) are carried out to quantify the impact of row spacing.

^{[14]}Comparison of the measured flow field with results from large eddy simulations (LES) combined with an actuator line approach is also presented for in-depth study of the induction field in the rotor plane.

^{[15]}1 shows the computed flow field from a high-fidelity simulation of the Lillgrund offshore wind farm using computational fl uid dynamics (CFD) with large-eddy simulation (LES) turbulence modeling and actuator line rotor aerodynamics models.

^{[16]}This numerical tool is a coupling between the Actuator Line Method (ALM) and the open-source, non-hydrostatic mesoscale atmospheric model Meso-NH, based on the Large Eddy Simulation (LES) framework.

^{[17]}Three test cases with the same mean velocity and different turbulence intensities are simulated numerically using the hybrid large eddy simulation/actuator line modelling technique.

^{[18]}In this work, large eddy simulations with an actuator line model are used to study downstream wake characteristics of the NREL 5 MW reference turbine mounted on the OC3-UMaine spar platform for several different metocean conditions.

^{[19]}In this work we show results of a validated numerical method [1], based on a Large Eddy Simulation-Actuator Line Model framework, applied to evaluate active power control on a real 7.

^{[20]}

## Unsteady Actuator Line

The coupled FOWT-UALM-SJTU solver is developed using the open source CFD package OpenFOAM, in which the unsteady actuator line model (UALM) is introduced into OpenFOAM for the aerodynamic simulation of wind turbine, while the hydrodynamic computation of floating platform is carried out with a two-phase CFD solver naoe-FOAM-SJTU.^{[1]}An unsteady actuator line model (UALM) is embedded into in-house code naoe-FOAM-SJTU to establish a fully coupled CFD analysis tool for numerical simulations of FOWTs.

^{[2]}, wave generation and absorption, 6 degrees of freedom motion, mooring system, dynamic overset grid, fluid-structure interaction, unsteady actuator line model, implemented on the open source platform OpenFOAM are introduced to illustrate the development of the marine hydrodynamics CFD solver.

^{[3]}An unsteady actuator line model (UALM) coupled with a two-phase computational fluid dynamics solver naoe-FOAM-SJTU is applied to solve three-dimensional Reynolds-averaged Navier–Stokes equations.

^{[4]}

## actuator line model

This study focuses on developing and applying an actuator line model (ALM) to predict the wake behind floating offshore wind turbines (FOWTs).^{[1]}The simulations are conducted using the actuator line model (ALM) coupled with a three-dimensional Navier Stokes solver implementing the k−ω shear stress transport turbulence model.

^{[2]}The turbines are taken into account using FAST (from NREL) and their effects are imposed into the fluid domain through an actuator line model (ALM) for which specific enhancements are proposed.

^{[3]}In the present study, an actuator line model code was implemented in the OpenFOAM flow solver.

^{[4]}Recently, actuator line model become popular in studying wind-turbine wakes.

^{[5]}Firstly, the wind turbine control algorithms including torque, pitch and yaw controls are implemented in LES with Actuator Line Model (ALM).

^{[6]}The effect of two pitch parameters (the fold angle and the incline angle) on the instantaneous aerodynamic forces and overall performance of a straight-bladed VAWT under a tip-speed ratio of 4 is investigated using an actuator line model, achieved in ANSYS Fluent software and validated by previous experimental results.

^{[7]}Turbulent flow fields behind wind turbines are investigated using LES and Actuator Line Model with OpenFOAM on locally clustered Cartesian grids in a parallel computing environment.

^{[8]}The purpose of this paper is to implement a CFD-based Computationally-Efficient approach based on an actuator line model (ALM) for FOWTs aerodynamics.

^{[9]}A hybrid Large Eddy Simulation (LES) / Actuator Line Model (ALM) computational approach is employed to simulate the turbulent wake of a two-bladed rotor in hover.

^{[10]}ROAM is Cartesian-based, employing an actuator line model for the rotor and an immersed boundary model for the fuselage.

^{[11]}And an Actuator Line Model supplies the CFD tool with body forces that mimic the impact of moving objects on the airflow, thus, avoiding computationally expensive dynamic meshing.

^{[12]}The actuator line model is used to predict the aerodynamic performance of wind turbine.

^{[13]}The turbine is taken into account using FAST (from NREL) and its effects are imposed into the fluid domain through an actuator line model.

^{[14]}In the present work, the near-wake generated for a vertical axis wind turbine (VAWT) was simulated using an actuator line model (ALM) in order to validate and evaluate its accuracy.

^{[15]}Actuator Line Model (ALM) combined with Large Eddy Simulation (LES) is a promising way to comprehend this phenomenon.

^{[16]}In this work the results of a validated numerical method, based on a Large Eddy Simulation-Actuator Line Model framework, was applied to simulate a real 7.

^{[17]}The coupled FOWT-UALM-SJTU solver is developed using the open source CFD package OpenFOAM, in which the unsteady actuator line model (UALM) is introduced into OpenFOAM for the aerodynamic simulation of wind turbine, while the hydrodynamic computation of floating platform is carried out with a two-phase CFD solver naoe-FOAM-SJTU.

^{[18]}In this study, a neutral atmospheric boundary layer and wind turbine blades were constructed in a large eddy simulation and actuator line model for conducting a field experiment of a wind turbine.

^{[19]}An unsteady actuator line model (UALM) is embedded into in-house code naoe-FOAM-SJTU to establish a fully coupled CFD analysis tool for numerical simulations of FOWTs.

^{[20]}A large eddy simulation and an actuator line model are introduced in the present work to simulate the wake field and aerodynamic loads of wind turbines with different longitudinal spacings.

^{[21]}To better simulate the wake-induced fatigue on wind turbine blades, a novel elastic actuator line model is employed in this study.

^{[22]}The turbine is represented using an actuator line model in a pseudo-spectral method-based solver.

^{[23]}The wind turbine is represented by the actuator line model (ALM).

^{[24]}, wave generation and absorption, 6 degrees of freedom motion, mooring system, dynamic overset grid, fluid-structure interaction, unsteady actuator line model, implemented on the open source platform OpenFOAM are introduced to illustrate the development of the marine hydrodynamics CFD solver.

^{[25]}In this paper, a validated CFD analysis tool FOWT-UALM-SJTU with modified actuator line model is applied for the coupled aero-hydrodynamic simulations of a spar-type FOWT system.

^{[26]}An unsteady actuator line model (UALM) coupled with a two-phase computational fluid dynamics solver naoe-FOAM-SJTU is applied to solve three-dimensional Reynolds-averaged Navier–Stokes equations.

^{[27]}In this work, large eddy simulations with an actuator line model are used to study downstream wake characteristics of the NREL 5 MW reference turbine mounted on the OC3-UMaine spar platform for several different metocean conditions.

^{[28]}The ASM appears to overcome the inadequacy of actuator line models to account for the flow blockage of the rotor blades when they are on the up-stream side of the revolution, because the ASM uses a surface instead of a line to represent the blade.

^{[29]}Rotors representation were introduced into computational domain by means of Actuator Line Model.

^{[30]}In this work we show results of a validated numerical method [1], based on a Large Eddy Simulation-Actuator Line Model framework, applied to evaluate active power control on a real 7.

^{[31]}

## actuator line method

We then perform large-eddy simulation (LES) of open-channel flow for 28 layouts of tidal turbines using an actuator line method with doubly periodic boundary conditions.^{[1]}The Actuator Line Method (ALM), combining a lumped-parameter representation of the rotating blades with the CFD resolution of the turbine flow field, stands out among the modern simulation methods for wind turbines as probably the most interesting compromise between accuracy and computational cost.

^{[2]}Large eddy simulations and an adaption of the actuator line method (in order to describe arbitrary paths) are used to study the turbulent flow with and without Deep Green for a specific site.

^{[3]}Analysis tools with a fidelity higher than the ubiquitous Blade Element Momentum (BEM) method are needed by now in wind energy; in particular, different research groups have recently proposed the application of the Actuator Line Method (ALM) to wind turbines, to exploit the benefits of an accurate discretization of the wake through Computational Fluid Dynamics and the computational cost saving associated to the lumped parameter modeling of the blade.

^{[4]}Among them, the Actuator Line Method (ALM) stands out in terms of accuracy and computational cost.

^{[5]}To simulate this interdependence, the actuator line method (ALM) has been implemented in the atmospheric code Meso-NH, which is an LES research code developed by the French weather services.

^{[6]}In this work, the mean flow streamtube around a single DTU 10MW wind turbine, under yaw misalignement and turbulent inflow is investigated with Large-Eddy Simulation combined to the Actuator Line method.

^{[7]}In this study, we analyze the near-wake characteristics of a 5-MW single wind turbine using a large-eddy simulation with the actuator line method.

^{[8]}A large-eddy simulation-actuator line method (LES-ALM) applied to a single horizontal axis tidal turbine is presented and validated against experimental data.

^{[9]}The numerical simulations adopt both the actuator line method and the full rotor geometry method.

^{[10]}To extend the knowledge about turbine-to-turbine interplay in tidal arrays, high-fidelity numerical simulations using a Large-Eddy Simulation-Actuator Line Method (LES-ALM) are carried out to quantify the impact of row spacing.

^{[11]}The subgrid model for the flow across the chordae tendineae is based on the Actuator Line Method, which means that they are represented by drag coefficients.

^{[12]}In this numerical study, the standard actuator line method is modified for simulating ducted tidal turbines and validated against experimental data for two turbines with different geometries.

^{[13]}This study focuses on the coupled aeroelastic wake behavior of the wind turbine and developed a new tool called ALFBM, which combines the Actuator Line Method (ALM) and the nonlinear finite element Beam theory.

^{[14]}ABSTRACT In this paper, first and second laws of thermodynamics are performed on MEXICO wind turbine based on a generalized Actuator Line method (ALM).

^{[15]}This numerical tool is a coupling between the Actuator Line Method (ALM) and the open-source, non-hydrostatic mesoscale atmospheric model Meso-NH, based on the Large Eddy Simulation (LES) framework.

^{[16]}The OpenFOAM package incorporated with actuator line method (ALM) is employed to calculate the aerodynamic characteristics of large wind turbines in an offshore wind farm.

^{[17]}

## actuator line technique

Actuator disc and actuator line techniques are widely used for modelling wind turbines operating in wind farms.^{[1]}The force smearing in the actuator line technique ensures its numerical stability, but also breaks its intended similarity to the lifting line by similarly smearing its vorticity in the flow domain.

^{[2]}

## actuator line approach

This paper applies a large-eddy actuator line approach to the simulation of wind turbine wakes.^{[1]}Comparison of the measured flow field with results from large eddy simulations (LES) combined with an actuator line approach is also presented for in-depth study of the induction field in the rotor plane.

^{[2]}