Actuator Disc Approach of Wind Turbine Wake Simulation Considering Balance of Turbulence Kinetic Energy

Abstract

The operation of the wind turbines downstream is affected by the wake of the wind turbines upstream. Wind turbine wake flow is investigated by applying the actuator disc (AD) method. The modified k-ε turbulence model is proposed by using both the turbulent kinetic energy source term and the dissipation rate source term to improve the standard k-ε turbulence model for coordinating the generation and the dissipation of the turbulent kinetic energy. The dissipation rate parameter C 4ε that obeys a parabolic distribution is used, based on theoretical analysis. The force distributed on the AD is also used instead of a constant, as used in the classical AD method. The simulation results were consistent with the measurements that correspond to different kinds of wind turbines and conditions. The nacelle and the inflow turbulence intensity have great influences on accurately simulating the wake, so it is necessary to imitate the rotor along with the nacelle and accurately measure the inflow turbulence intensity. been continually developing [11]. The engineering "wake model" was established earlier and has a simple structure and short calculation time. The most famous Jensen model, which is also the basic model of the commonly used commercial wind resources software WAsP, was proposed to evaluate the wind turbine wakes on flat terrain [12]. The eddy viscosity model appeared as another analytical wind turbine wakes model and was used in the commercial wind resources software WindFarmer belonging to the Garrad Hassan company [13]. These models are based on assumptions of the flow behavior, such as axisymmetry and self-similarity. They work fast and are suitable for engineering applications, but they cannot predict wake accurately. The blade model can be constructed directly in the flow field and used to precisely calculate the load of the wind turbine and other aspects related to wind turbine performance [14]. Qian Y.R. used this method to predict the air-load with different wind speeds under yaw conditions [15]. However, this method needs more grids around the blade and a lot of computing resources; therefore, it does not apply to multiple wind turbines or wind farm scales. The actuator line model simplifies the blade into a line which is rotated as the blade, then constructs a functional relationship between the aerodynamic data of the blade's local section airfoil and body force, so that it can simulate the interaction between the blade and the inflow [16]. The actuator line model, combined with the large eddy simulation (LES) method, was used to investigate the near wake region and explain the reason why the velocity deficit and turbulence intensity increase nearby the rotor [17]. Storey R.C. coupled the model with multi-physics method in order to research the wind turbine performance under transient conditions [18]. The actuator line model also can demonstrate the wake of the wind turbine over complex terrain and reduce the cost of wind farm simulation to a certain extent [19], but it still takes a lot of computing res...

Numerical simulation of wind turbine wake based on extended k‐epsilon turbulence model coupling with actuator disc considering nacelle and tower

“… means the kinematic molecular viscosity and shows the turbulent eddy viscosity. The model constants , , , , are determined according to the neutral atmosphere boundary layer, and , , , , [29].…”

“…Therefore, some modified turbulence models by the way of directly limiting the turbulence viscosity based on the velocity gradients were revisited, and model of Shih and model were recommended by van der Laan and Andersen [27]. Of course, there have also been several turbulence models by indirectly limiting the viscosity, such as model of Kasmi and Masson [28], model of Ren [29] and model of Tian [30], which help to improve the effect of wind turbine wake simulation. Consequently, the ADM incorporated into RANS‐based turbulence model, like the type of turbulence model or the modified one, has obvious advantages to simulate wind farm wake.…”

Variable Renewable Energy and Market Design: New Products and a Real-World Study

“…Now, considering existing and emerging market products associated with VRE producers and BMs, the provision of reactive power may be considered an important product [24]. Also, primary reserve is a potential product for VRE producers, contributing to compensate the disadvantage of a reduced inertia in power systems with high levels of VRE [25]. Photovoltaic systems do not have mass inertia and can adjust their output within milliseconds.…”

Numerical investigation of shallow-water effects on hydrokinetic turbine wake recovery

“…A review of the literature shows that CFD simulations have been used to either understand the effects of free-stream turbulence [4], topography and boundary layer [5,6], dynamic motions of the platform [7], etc. on power production and loading on turbines; and prediction of turbine wake recovery for a single turbine [8] or those in an array [9,10] to estimate appropriate array design [11]. Some studies have been performed to study the effect of the air-water interface on HKT performance and wake recovery.…”