## What is/are Actuator Disc?

Actuator Disc - In this code, three new additions are made; the forest model, the mesh modification for complex terrain and the representation of the WT using an actuator disc model with local force adaptation for wind farm flows.^{[1]}Analysis of array thrust, power and wakes was conducted using a RANS actuator disc model and assessed against new experimental measurements using porous discs.

^{[2]}Funding information Research Council of Norway, Grant/Award Numbers: 254845/O80, 268044 A novel approach for the modeling of rotor-integrated aerodynamic loads is suggested to answer the need for a comprehensive, insightful, and analytical actuator disc model.

^{[3]}First, we present a theoretical analysis based on an extension of the linear momentum actuator disc theory for perfectly aligned and staggered layouts, employing a hybrid inviscid-viscous approach to account for the local blockage effect within each row of turbines and the viscous (turbulent) wake mixing behind each row in a coupled manner.

^{[4]}This paper uses an actuator disc to model the effect of the propeller.

^{[5]}To simulate the rotor downwash from the coaxial rotors, the Actuator Disc approach is used.

^{[6]}As the investigation of a rotating turbine can be challenging, both experimentally and numerically, static actuator discs can substitute rotating turbines.

^{[7]}A numerical study to investigate the characteristics of flow around two DWT configurations using a simplified duct-actuator disc (AD) model is carried out.

^{[8]}The diffuser total efficiency was formulated and defined based on the generalized actuator disc model for the index of the efficiency of the diffuser-alone of the diffuser-augmented wind turbines.

^{[9]}By using actuator disc model, the horizontal and vertical velocity profiles behind the wind farm are analyzed.

^{[10]}In this study, we employ CFD coupled with an Actuator Disc model to analyze interactions of two tandem FOWTs for the scenario, where the upstream rotor is floating with a prescribed surge motion and the downstream rotor is fixed and influenced by the variations in the incoming flow created by the oscillating motion of the surging rotor.

^{[11]}The results show that the "BAB" actuator discharges more stable than the conventional actuator after discharge aging for 4 hours, and the plasma was more uniform without obvious discharge channels.

^{[12]}Furthermore, the actuator disc theory adjusted for open channel flow has been compared and found in consonance with the experimental results.

^{[13]}Previous research hypothesised that this phenomena can result in a turbulent wake state or even a vortex ring state, invalidating the Actuator Disc Momentum Theory and the use of the Blade Element Momentum Theory.

^{[14]}Actuator disc theory is used, as it allows the aerodynamic behaviour of a wind turbine to be analyzed by just considering the energy extraction process without a specific wind turbine design.

^{[15]}Therefore, to make the water egress problem more tractable to solve, various modeling simplifications -such as the use of an actuator disc methodology for propeller flow modeling and Wong's terramechanics methodology for the wheel / ramp interaction -were introduced to facilitate rapid simulation.

^{[16]}This paper provides two examples of the LAM, the Lagrangian actuator line (LAL) model and the Lagrangian actuator disc (LAD) model, and constructs matching numerical methods for wake predictions respectively.

^{[17]}Meso-scale models typically represent turbines as actuator discs that act as momentum sinks and sources of turbulence and its dissipation.

^{[18]}The aerodynamic design of a ducted wind turbine for maximum total power coefficient was studied numerically using the axisymmetric Reynolds-averaged Navier-Stokes equations and an actuator disc model.

^{[19]}Taking into account the presence of wind shear effect and the vertical profiles of flow quantities in the atmospheric boundary layer flow, a numerical simulation of complex wind-turbine wakes is conducted by solving the Reynolds-averaged Navier–Stokes equations, with a simple actuator disc model implemented for the rotor effects.

^{[20]}The aerodynamic design of a ducted wind turbine for maximum total power coefficient was studied numerically using the axisymmetric Reynolds-averaged Navier–Stokes equations and an actuator disc model.

^{[21]}The device is modelled using actuator disc theory in which we allow the device to be split into arrays and these then into sub-arrays an arbitrary number of times so as to construct an $n$-level multi-scale device in which the original device undergoes $n-1$ sub-divisions.

^{[22]}The model is based upon conservation of momentum in the context of actuator disc theory, and the assumption of a distribution of the double-Gaussian type for the velocity deficit in the wake.

^{[23]}Actuator disc and actuator line techniques are widely used for modelling wind turbines operating in wind farms.

^{[24]}Recently, a new tool (Actuator Disc) based on the Momentum Actuator Disc Theory (MADT) was developed in Delft3D-FLOW, overcoming the aforementioned limitations and showing excellent results against laboratory data.

^{[25]}The aim of the present study is to perform a comparative analysis of two actuator disc methods (ACD) and two analytical wake models for wind farm power production assessment.

^{[26]}A numerical study to investigate the characteristics of flow around the DWT using a simplified duct–actuator disc (AD) model is carried out.

^{[27]}Actuator disc models, such as the two-scale actuator disc theory, have proven useful in seeking optimal turbine arrangements, yet these models assume flows that are frictionless and steady, and thus quite unlike the channel flow conditions that actual tidal turbines experience.

^{[28]}The Actuator Disc/Navier-Stokes (AD/NS) method has played a significant role in wind farm simulations.

^{[29]}The hierarchies of aerodynamic models for wind turbines in increasing the order of complexity, cost, and fidelity are blade element momentum (BEM) theory (BEMT), vortex methods, actuator disc/line methods, and blade -resolved modeling.

^{[30]}In this paper, for the first time, an advanced numerical method for wind farm assessment is developed, which consists of a Reynolds averaged Navier-Stokes - Actuator Disc model for the flow modelling, a semi-engineering model for the noise source modelling, and a parabolic wave equation model for the sound propagation modelling.

^{[31]}In the past, several models have been developed for an actuator disc under yawed conditions, but they are subject to various assumptions.

^{[32]}This work aims to study the impact of an unsteady actuator disc on the wake flow field using a free wake vortex ring model.

^{[33]}A way to quantified diffuser-rotor interaction is presented for a micro-diffuser-augmented hydrokinetic turbine (MDAHT) base on the actuator disc theory (Jamieson, 2011).

^{[34]}The results of PAC actuator discharge indicate that inlet air temperature has a small increase of 4–9 K.

^{[35]}The Reynolds-averaged Navier–Stokes (RANS)-based generalized actuator disc method along with the Reynolds stress model (AD/RANS_RSM) is assessed for wind turbine wake simulation.

^{[36]}The results demonstrate that, despite its simplicity, the actuator disc model can give very useful information when developing a wind farm in neutral atmospheric conditions.

^{[37]}We find that, as compared to the idealised actuator disc, the importance of tuning is significantly reduced for the more realistic tidal rotor, and that this is particularly true for rotors with fixed blade pitch.

^{[38]}The models are developed using the differential form of Duhamel integrals of indicial responses of actuator disc type vortex models.

^{[39]}Ahead of the elaborate rotor optimisation modelling that would support detailed design, it is shown that significant insight and new design directions can be indicated with simple, high-level analyses based on actuator disc theory.

^{[40]}Actuator disc models are frequently used to provide a semi-analytical approach to estimating aerodynamic loads on rotary blades.

^{[41]}To precisely simulate wake interaction, the most common simplified wind turbine model, the Actuator Disc (AD) model, is improved adding the capability to adapt the thrust force distribution to a non-uniform velocity field over the disc, and the orientation to different local wind directions.

^{[42]}Subsequently, we compare the wakes resulting from simple models (a circular cylinder and an actuator disc) to the time averaged cross-flow turbine wakes.

^{[43]}The wind turbines are modelled as actuator discs, and two design variables per wind turbine collective pitch, α, and tip speed ratio, λ are initially defined for the optimization problem.

^{[44]}Arrays of turbines modelled using the volume-flux-constrained actuator disc and blade element momentum theories are embedded within onedimensional analytical and two-dimensional numerical channel domains.

^{[45]}A numerical study to investigate the characteristics of flow around two DWT configurations using a simplified duct-actuator disc (AD) model is carried out.

^{[46]}He derived momentum equations of an Actuator Disc (AD) in the stream.

^{[47]}The method involves two parts: calculation of the wind speed distribution using computational fluid dynamics, with the rotor modeled as a uniform loaded actuator disc, and calculation of the tower drag via the strip theory.

^{[48]}In confirmation, these outcomes were subsequently analysed by means of actuator disc theory, attaining a distinguishable relationship with blade-integrated outcomes.

^{[49]}An analysis of the exhaust diffuser section of a gas turbine is presented by incorporating the reduced order mathematical model “actuator disc concept” that represents the last stage of the turbine.

^{[50]}

## Generalized Actuator Disc

The diffuser total efficiency was formulated and defined based on the generalized actuator disc model for the index of the efficiency of the diffuser-alone of the diffuser-augmented wind turbines.^{[1]}The Reynolds-averaged Navier–Stokes (RANS)-based generalized actuator disc method along with the Reynolds stress model (AD/RANS_RSM) is assessed for wind turbine wake simulation.

^{[2]}The project focuses on numeric investigations of the Generalized Actuator Disc (GAD)theory.

^{[3]}

## Momentum Actuator Disc

First, we present a theoretical analysis based on an extension of the linear momentum actuator disc theory for perfectly aligned and staggered layouts, employing a hybrid inviscid-viscous approach to account for the local blockage effect within each row of turbines and the viscous (turbulent) wake mixing behind each row in a coupled manner.^{[1]}Recently, a new tool (Actuator Disc) based on the Momentum Actuator Disc Theory (MADT) was developed in Delft3D-FLOW, overcoming the aforementioned limitations and showing excellent results against laboratory data.

^{[2]}

## actuator disc model

In this code, three new additions are made; the forest model, the mesh modification for complex terrain and the representation of the WT using an actuator disc model with local force adaptation for wind farm flows.^{[1]}Analysis of array thrust, power and wakes was conducted using a RANS actuator disc model and assessed against new experimental measurements using porous discs.

^{[2]}Funding information Research Council of Norway, Grant/Award Numbers: 254845/O80, 268044 A novel approach for the modeling of rotor-integrated aerodynamic loads is suggested to answer the need for a comprehensive, insightful, and analytical actuator disc model.

^{[3]}The diffuser total efficiency was formulated and defined based on the generalized actuator disc model for the index of the efficiency of the diffuser-alone of the diffuser-augmented wind turbines.

^{[4]}By using actuator disc model, the horizontal and vertical velocity profiles behind the wind farm are analyzed.

^{[5]}In this study, we employ CFD coupled with an Actuator Disc model to analyze interactions of two tandem FOWTs for the scenario, where the upstream rotor is floating with a prescribed surge motion and the downstream rotor is fixed and influenced by the variations in the incoming flow created by the oscillating motion of the surging rotor.

^{[6]}The aerodynamic design of a ducted wind turbine for maximum total power coefficient was studied numerically using the axisymmetric Reynolds-averaged Navier-Stokes equations and an actuator disc model.

^{[7]}Taking into account the presence of wind shear effect and the vertical profiles of flow quantities in the atmospheric boundary layer flow, a numerical simulation of complex wind-turbine wakes is conducted by solving the Reynolds-averaged Navier–Stokes equations, with a simple actuator disc model implemented for the rotor effects.

^{[8]}The aerodynamic design of a ducted wind turbine for maximum total power coefficient was studied numerically using the axisymmetric Reynolds-averaged Navier–Stokes equations and an actuator disc model.

^{[9]}Actuator disc models, such as the two-scale actuator disc theory, have proven useful in seeking optimal turbine arrangements, yet these models assume flows that are frictionless and steady, and thus quite unlike the channel flow conditions that actual tidal turbines experience.

^{[10]}In this paper, for the first time, an advanced numerical method for wind farm assessment is developed, which consists of a Reynolds averaged Navier-Stokes - Actuator Disc model for the flow modelling, a semi-engineering model for the noise source modelling, and a parabolic wave equation model for the sound propagation modelling.

^{[11]}The results demonstrate that, despite its simplicity, the actuator disc model can give very useful information when developing a wind farm in neutral atmospheric conditions.

^{[12]}Actuator disc models are frequently used to provide a semi-analytical approach to estimating aerodynamic loads on rotary blades.

^{[13]}

## actuator disc theory

First, we present a theoretical analysis based on an extension of the linear momentum actuator disc theory for perfectly aligned and staggered layouts, employing a hybrid inviscid-viscous approach to account for the local blockage effect within each row of turbines and the viscous (turbulent) wake mixing behind each row in a coupled manner.^{[1]}Furthermore, the actuator disc theory adjusted for open channel flow has been compared and found in consonance with the experimental results.

^{[2]}Actuator disc theory is used, as it allows the aerodynamic behaviour of a wind turbine to be analyzed by just considering the energy extraction process without a specific wind turbine design.

^{[3]}The device is modelled using actuator disc theory in which we allow the device to be split into arrays and these then into sub-arrays an arbitrary number of times so as to construct an $n$-level multi-scale device in which the original device undergoes $n-1$ sub-divisions.

^{[4]}The model is based upon conservation of momentum in the context of actuator disc theory, and the assumption of a distribution of the double-Gaussian type for the velocity deficit in the wake.

^{[5]}Recently, a new tool (Actuator Disc) based on the Momentum Actuator Disc Theory (MADT) was developed in Delft3D-FLOW, overcoming the aforementioned limitations and showing excellent results against laboratory data.

^{[6]}A way to quantified diffuser-rotor interaction is presented for a micro-diffuser-augmented hydrokinetic turbine (MDAHT) base on the actuator disc theory (Jamieson, 2011).

^{[7]}Ahead of the elaborate rotor optimisation modelling that would support detailed design, it is shown that significant insight and new design directions can be indicated with simple, high-level analyses based on actuator disc theory.

^{[8]}In confirmation, these outcomes were subsequently analysed by means of actuator disc theory, attaining a distinguishable relationship with blade-integrated outcomes.

^{[9]}She used actuator disc theory to represent the turbines following [9].

^{[10]}

## actuator disc method

The aim of the present study is to perform a comparative analysis of two actuator disc methods (ACD) and two analytical wake models for wind farm power production assessment.^{[1]}The Reynolds-averaged Navier–Stokes (RANS)-based generalized actuator disc method along with the Reynolds stress model (AD/RANS_RSM) is assessed for wind turbine wake simulation.

^{[2]}

## actuator disc concept

An analysis of the exhaust diffuser section of a gas turbine is presented by incorporating the reduced order mathematical model “actuator disc concept” that represents the last stage of the turbine.^{[1]}The derivations show that the actuator disc concept is indispensable in order to recover Froude's theorem.

^{[2]}