Linyue Gao

University of Colorado | UCD · Department of Mechanical Engineering

Wind direction variability with height, known as “wind veer,” results in power losses for wind turbines that rely on single-point wind measurements at the turbine nacelles. To address this challenge, we introduce a novel yaw control strategy designed to optimize turbine alignment by adjusting the yaw angle based on specific wind veer conditions, th...

Wind energy represents a promising alternative to replace traditional fossil-based energy sources. For this reason, increasing the efficiency in the conversion process from wind to electrical energy is crucial. Unfortunately, the presence of systematic errors (mostly related to the yaw and pitch angles) is one of the key factors causing underperfor...

Wind turbine blade icing seriously affects turbine power generation and fatigue life, and an accurate diagnosis of blade icing is beneficial for wind turbines to make in-time adjustments. However, the high dimensional and unbalanced original data recorded by Supervisory Control and Data Acquisition (SCADA) systems pose great challenges to the accur...

Much attention in the wind energy literature is devoted to condition monitoring [...]

In this chapter, the basic concepts of conventional icing mitigation methods are introduced. The working mechanisms and implementation restrictions of the various icing mitigation techniques, such as control-based, anti-/de-icing fluids, mechanical and thermal approaches, are summarized, compared, and analyzed. This chapter focuses on the icing mit...

This chapter provides a summary of past and ongoing icing-related research projects globally, including but not limited to icing physics, ice detection, ice prediction, and ice mitigation techniques. Inspired by these investigations, we provide recommendations for the safer operation of wind turbines in cold and wet environments and suggestions for...

In this chapter, the potentials of various promising hydro-/ice-phobic coatings/materials for wind turbine mitigation are illustrated and evaluated in great detail. The state-of-the-art hydro-/ice-phobic coatings/materials available in the market (or underdevelopment) can be generally divided into three categories: (1) superhydrophobic surfaces wit...

This chapter focuses on the measurement techniques used to quantify ice structures accreted over the wind turbine blade surfaces. Ice shape quantification plays an essential role in the follow-on computational or experimental icing physics studies and development of anti-/de-icing strategies. Up to now, the ice shape documentation methods include s...

In this chapter, we will report a novel icing mitigation method that utilizes the thermal effects induced by DBD plasma actuation to prevent/remove the dynamic ice accretion on wind turbines. The fundamental mechanisms of thermal energy generation in DBD plasma discharges will be introduced first. Then, a comparison between the working mechanisms o...

This chapter covers the state-of-the-art ice detection techniques for wind turbines operated in cold climates and the risk matrix to evaluate wind turbine icing events based on field measurements. The ice detection techniques can be categorized into direct and indirect detection methods, depending on the weather/operational sensors used for the fie...

This chapter discusses the fundamental physics in ice accretion over wind turbine surfaces under various icing conditions. The key parameters influencing the impact icing process on wind turbines are described in great detail. The two stages of ice accretion on a wind turbine are illustrated, that is, (i) the dynamic water droplets impinging proces...

The 2021 Texas power crisis has highlighted the vulnerability of the power system under wind extremes, particularly with the increasing penetration of energy resources that depend on weather conditions (e.g., wind energy). The current wind power forecast models do not effectively consider the impact of such extreme weather events. In the present st...

In recent years, wind turbine yaw misalignment that tends to degrade the turbine power production and impact the blade fatigue loads raises more attention along with the rapid development of large-scale wind turbines. The state-of-the-art correction methods require additional instruments such as laser imaging detection and ranging to provide the gr...

A field campaign was carried out to investigate ice accretion features on large turbine blades (50 m in length) and to assess power output losses of utility-scale wind turbines induced by ice accretion. After a 30-h icing incident, a high-resolution digital camera carried by an unmanned aircraft system was used to capture photographs of iced turbin...

The 2021 Texas power crisis has highlighted the vulnerability of the power system under wind extremes, particularly with the increasing penetration of energy resources that depend on weather conditions (e.g., wind energy). The current wind power forecast models do not effectively consider the impact of such extreme weather events. In the present st...

In recent years, wind turbine yaw misalignment that tends to degrade the turbine power production and impact the blade fatigue loads raises more attention along with the rapid development of large-scale wind turbines. The state-of-the-art correction methods require additional instruments such as LiDAR to provide the ground truths and are not suitab...

The wind industry in cold climates has shown strong growth in recent years, but turbine icing in these regions can cause significant energy loss leading to a reduction in reliability of wind energy. Previous studies on estimating wind turbine icing (WTI) generally rely on complex physical models, and many only model the ice growth itself while fail...

Icing significantly affects the performance of wind turbines in terms of power loss and structural degradation, and an effective blade icing diagnosis is the prerequisite to achieve the optimal control of wind turbines to mitigate such icing influence. However, current icing diagnostic methods lack consideration of fundamental icing physics and hav...

A critical review is provided to summarize our recent efforts to utilize the state‐of‐the‐art bio‐inspired icephobic coatings/surfaces, i.e., 1). Lotus‐leaf‐inspired superhydrophobic surfaces (SHS) and 2). Pitcher‐plant‐inspired slippery liquid‐infused porous surfaces (SLIPS) for aircraft icing mitigation. By leveraging the unique Icing Research Tu...

Wind direction variation with height (wind veer) plays an essential role in the inflow wind field as the wind turbine enlarges. We explore the wind veer characteristics and their impact on turbine performance using a 5-year field dataset measured at the Eolos Wind Energy Research Station of the University of Minnesota. Wind veer exhibits an appreci...

Over 30% worldwide installations of wind turbines in cold climate regions are threatened with icing risks. The current study presents a systematic characterization of the turbine operation, power production, and blade/ tower structural responses of a utility-scale wind turbine (2.5 MW, variable-speed variable-pitch regulated) under natural icing en...

A field study was conducted to examine ice accretion on 50-m-long turbine blades and icing-induced power production losses to multi-megawatt wind turbines. An unmanned-aerial-system equipped with a digital camera was deployed to take images of the ice structures on turbine blades after undergoing a 30-hour-long icing event to quantify the ice thick...

An experimental study was conducted to explore the potentials of using a Slippery-Liquid-Infused-Porous-Surface (SLIPS) for wind turbine icing mitigation. The SLIPS was prepared by infusing a lubricant oil into a nanofibrous membrane, which can stick firmly to the surface of a turbine blade model. While the SLIPS was found to effectively suppress i...

The potential airborne transmission of COVID-19 has raised significant concerns regarding the safety of musical activities involving wind instruments. However, currently, there is a lack of systematic study and quantitative information of the aerosol generation during these instruments, which is crucial for offering risk assessment and the correspo...

The potential airborne transmission of COVID-19 has raised significant concerns regarding the safety of musical activities involving wind instruments. However, currently, there is a lack of systematic study and quantitative information of the aerosol generation during these instruments, which is crucial for offering risk assessment and the correspo...

A critical review is provided to summarize our recent efforts to utilize the state-of-the-art bio-inspired icephobic coatings/surfaces, i.e., 1). Lotus-leaf-inspired superhydrophobic surfaces (SHS) and 2). Pitcher-plant-inspired slippery liquid-infused porous surfaces (SLIPS) for aircraft icing mitigation. By leveraging the unique Icing Research Tu...

A better understanding of the intense interaction between the turbulent inflow and rotating wind turbine components is critical to accelerating the path towards larger wind turbines. The present investigation provides the first field characterization of the influence of turbulent inflow on the blade structural response of a utility-scale wind turbi...

Icing events, particularly under precipitation-icing conditions in which high-liquidity glaze ice tends to form, could pose significant threats to the safe and effective operations of wind turbines in cold and wet environments. During the glaze ice accretion process, the wind-driven unfrozen water was coupled with the growth of ice structures and d...

The present investigation provides the first field characterization of the influence of turbulent inflow on the blade structural response of a utility-scale wind turbine (2.5MW), using the unique facility available at the Eolos Wind Energy Research Station of the University of Minnesota. A representative one-hour dataset under a stable atmosphere i...

An experimental study was conducted to examine the dynamic ice accretion process over the surface of a high-voltage power transmission cable model and characterize the effects of the ice accretion on the aerodynamic forces acting on the test model. The experimental study was carried out by leveraging the unique Icing Research Tunnel of Iowa State U...

Wind turbine wakes effects are critical issues for large wind farms. With the increasing dimensions of wind turbines and wind farms, there are strong interactions between the wind turbine wakes and atmospheric boundary layer (ABL). In this study, we focus on the daily variation of characteristics of ABL and its impact on the development of wind tur...

Power loss caused by wind speed deficit in wind turbine wake is a critical issue for wind farms. Various engineering wake models have been developed and applied to predict velocity distribution in wind turbine wake and wind farm power production. In this study, three widely used wind turbine wake models, Jensen, Frandsen and Larsen model, were comp...

In wind farms, the performance of downstream wind turbines is significantly affected by the upstream turbine wakes. In this study, we focus on the wake interactions of two horizontal-axis wind turbines, and the separation distance has been investigated using a Reynolds-averaged Navier-Stokes (RANS) framework. Three models for two in-line turbines a...

Wind shear inflow conditions with different indices lead to different wind speed distributions in wind turbine wakes, which further affects the power output of downstream turbines. In this study we focus on wind turbine wake considering different inflow shear indices. The three-dimensional numerical simulation, based on the full NREL 5 MW wind turb...

Wind turbine wakes and their interactions with atmospheric boundary layer (ABL) flows have a significant impact on the performance of wind turbines and wind farms, and thus it is essential to understand the flow dynamics imposed by ABL flows and wind turbine wakes. In this study, we focus on the impact of ambient turbulence on wind turbine wakes in...

Gurney flap and trailing-edge wedge are useful devices to improve the aerodynamic performance of aerofoils for wind turbines; however, the researches on blunt trailing-edge aerofoil are limited. In this paper, we focus on the flow mechanism of Gurney flaps and trailing-edge wedges and their impacts on a blunt trailing-edge aerofoil DU97-W-300. Two-...

With the up-scaling of wind farms, wake effect has become a major factor which restricts wind power generation. Accurate simulation of the wind turbine wake velocity decay is of great significance to improve the current situation. Against the limitation of the neutral atmospheric hypothesis in wake simulation, the impact of atmospheric stability is...

Vortex generators (VGs) are commonly-used effective flow separation control devices, and are proved to have potential to improve the aerodynamic performance of large wind turbines. In this paper, the flow physics of VGs and how their size affects the aerodynamic performance of a blunt trailing-edge airfoil DU97-W-300 have been investigated using CF...

Vortex generators and trailing-edge wedges are proposed to be adopted simultaneously to enhance aerodynamic performance of a blunt trailing-edge airfoil for wind turbines. To understand the impact and physics of these two devices on airfoil performance, investigation was carried out by numerical simulation on DU97-W-300 using CFD. Three-dimensional...

In recent years, the accuracy of the wind power prediction has been urgently studied and improved to satisfy the requirements of power system operation. In this paper, the relevance vector machine (RVM)-based models are established to predict the wind power and its interval for a given confidence level. An NWP improvement module is presented consid...