Wind Gust Conditions Research Articles

A decision-tree-based measure–correlate–predict approach for peak wind gust estimation from a global reanalysis dataset

Abstract. Peak wind gust (Wp) is a crucial meteorological variable for wind farm planning and operations. However, for many wind farm sites, there is a dearth of on-site measurements of Wp. In this paper, we propose a machine-learning approach (called INTRIGUE, decIsioN-TRee-based wInd GUst Estimation) that utilizes numerous inputs from a public-domain reanalysis dataset and, in turn, generates multi-year, site-specific Wp series. Through a systematic feature importance study, we also identify the most relevant meteorological variables for Wp estimation. The INTRIGUE approach outperforms the baseline predictions for all wind gust conditions. However, the performance of this proposed approach and the baselines for extreme conditions (i.e., Wp>20 m s−1) is less satisfactory.

Real-time prediction framework for frequency-modulated multirotor noise

A comprehensive multirotor noise assessment framework is developed to predict the noise of rotational-speed-controlled rotor configurations in real-time. The key objectives are to synthesize the frequency-modulated multirotor noise and analyze the frequency modulation (FM) characteristics. The framework includes modules associated with the flight control, aerodynamics, time reconstruction, noise prediction, and time-frequency analysis (TFA). In addition to the hybrid blade element momentum model, the aerodynamics module contains a linear inflow model, a Beddoes wake model, and an unsteady aerodynamic correction model. The convective form and source-time dominant algorithms are used in the acoustic analogy for tonal noise prediction. The FM characteristics are identified using the synchrosqueezing-based high-resolution TFA for strongly non-stationary signals. The framework is verified through validation and verification studies for diverse rotor configurations and flight conditions. During the cruise flight of the multirotor, the tonal noise exhibits simultaneous frequency and amplitude modulations. In wind gust conditions, these modulations result from rotational speed variations, acoustic wave interference, and Doppler shifting. By clarifying the non-stationary noise signal in diverse flight environments, the proposed framework can facilitate noise assessment in the perception-influenced design stage of multirotor configurations.

A Study on Directly Interconnected Offshore Wind Systems during Wind Gust Conditions

An investigation of the effects of wind gusts on the directly interconnected wind generators is reported, and techniques toward the mitigation of the wind gust negative influences have been proposed. Using a directly interconnected system approach, wind turbine generators are connected to a single synchronous bus or collection grid without the use of power converters on each turbine. This bus can then be transformed for transmission onshore using High Voltage Alternating Current, Low-Frequency Alternating Current or High Voltage Direct Current techniques with shared power conversion resources onshore connecting the farm to the grid. Analysis of the potential for instability in transient conditions on the wind farm, for example, caused by wind gusts is the subject of this paper. Gust magnitude and rise time/fall time are investigated. Using pitch control and the natural damping of the high inertial offshore system, satisfactory overall system performance and stability can be achieved during these periods of transience.

Aerodynamic characteristics of an aerostat under unsteady wind gust conditions

An analysis of the effect of wind gusts on the aerodynamic characteristics of an aerostat is presented in this study. A three dimensional computational fluid dynamics based flow analysis of an aerostat using the realizable k−ϵ model is presented. The performance of the aerostat is analyzed by varying the angle of attack, gust amplitude, gust duration, gust velocity profile and the aerostat shape. Actual wind data is used to formulate the gust parameters used for the study. It is found that the aerostat drag is unaffected by the angle of attack because of the streamlined structure. A trade-off between the drag and lift values suggests the use of a slight positive angle of attack for the stable operation of the aerostat. A gust with a short rising or falling time with small amplitude is severe than the symmetric gust with larger amplitude and a slower rising or falling profile. A scaling methodology for the aerodynamic characteristics of the aerostat for different angles of attack, gust amplitudes, gust duration and aerostat shapes is presented. The scaling obtained for different angles of attack and gust amplitudes is linear, whereas for different gust duration the scaling is not linear.

Pilot Assessment of Fault-Tolerant PID Flight Controller for Elevator Efficiency Reduction via Hardware-In-the-Loop Simulations

This note presents the pilot assessment of a Fault-Tolerant Control (FTC) law for elevator efficiency reduction via Hardware-In-the-Loop Simulations (HILS) with a research airplane MuPAL-α. The FTC is supposed to be a PID controller from the viewpoint of the practicality and applicability viz., conventional Stability/Control Augmentation System (S/CAS) structure is adopted. The PID-FTC is designed with the consideration of onboard actuator uncertainties as well as the possible loss of efficiency (from 0% loss up to 80% loss) in the framework of H∞ control with hinfstruct command implemented in Matlab®. In HILS, the pilot is required to have steady climb and descent under the condition that the elevator efficiency is gradually reduced in a software level. HILS results indicate that the designed PID-FTC works well when the elevator efficiency decreases even under wind gust conditions.

Frequency and voltage control of microgrid with high WECS penetration during wind gusts using superconducting magnetic energy storage

The intermittent behavior of wind power generation results in a fast variation of both frequency and voltage magnitudes of isolated microgrids with high wind power penetration. In this paper, a hybrid energy microgrid with wind energy conversion system (WECS) and diesel synchronous generators are analyzed during wind gust conditions. Superconducting magnetic energy storage (SMES) is connected at the same node of the WECS to mitigate the intermittent wind power generation. A developed fuzzy logic controller has been applied to achieve active power sharing. The damping of voltage fluctuation depends on SMES reactive power, which is controlled by a voltage source converter. The studied microgrid comprises 33 nodes, two diesel SGs, and two WECSs of squirrel cage induction generator type at 30% penetration level. The results demonstrate the effectiveness of the proposed control strategy to mitigate the frequency fluctuations during the wind speed gusts by smoothing power output from WECSs/SMES system. Moreover, voltage control is achieved by injecting reactive power from the SMES system. All simulations are performed by MATLAB/Simulink package.

High-Resolution Wind Simulation over Incheon International Airport with the Unified Model’s Rose Nesting Suite from KMA Operational Forecasts

This study employs the Unified Model (UM) with the rose nesting suite at 300-m resolution to construct a high spatial and temporal resolution wind simulation model for predicting wind gusts over the Incheon International Airport (IIA). The model can enable efficient aircraft operation and avert accidents due to sudden wind gusts. Simulation results with different inputs from the Korea Meteorological Administration (KMA) operational data assimilation and prediction systems are compared with an observed dataset. The 300-m nested prediction systems are built using the 17 km Global Prediction System (GDAPS) and 1.5 km Local Prediction System (LDAPS) of KMA. They are downscaled to 300 m resolution using five and three nesting domains from the GDAPS and LDAPS, respectively. The model results are validated against automated weather stations (AWS) to determine the accuracy of the UM for simulating high-resolution winds over the IIA. Both nesting suites are identical, with the only difference being their initial (IC) and lateral boundary conditions (LBC). The major difference between LDAPS and GDAPS downscaled model results is that the GDAPS downscaled system has a lower wind direction RMSE and the LDAPS downscaled system has a lower wind speed RMSE for up to 48 hours of verification against observations; thus, it is better than the GDAPS downscaled system. Two case studies were performed; one for wind gust conditions and one for vertical wind shear over the IIA. The 300 m model performs better in both cases, making it useful for wind gust and wind shear predictions over the airport.

Smart Over Speed Protection of Zafarana Grid-connected Wind Farm during Wind Gust Conditions

The increasing share of renewable energy in electricity generation requires an effective operation and protection scheme using Smart Grid (SG) technologies. Smart meters of SG allow the transfer of the measured signals in the wind farm to the operation and protection centre of the SG. Such signals transmission can improve the farm performance and reduce system cost. The secure operation of wind farms requires an efficient over speed protection of the turbines under wind gust conditions. Therefore, this paper is concerned with integration of a new over speed protection algorithm with the existing protection centre in SG. The main objective of the proposed algorithm is the dynamic updating of Critical Clearing Time (CCT) for over speed protective relays against severe wind gusts to minimize loss of life and component damage. In this respect, long-term data of wind speed of Zafarana farm have been collected and processed to define gust intensity and its distribution Moreover, the geographical farm area is classified to different rows according to the recorded gust values. A smart relay setting will be formulated by developing heuristic algorithm, which relates CCT with the gust intensity, and its row along the geographical area of Zafarana farm. Accordingly, general two variables second order function will propose to identify the dynamic CCT based on wind speed measured by smart meters installed on each wind farm row. The digital relay settings are updated according to the determined CCT using the communication facilities existing in the SG. The simulation results indicate that the proposed over speed protection improves significantly the performance of the grid connected wind farm under wind gust conditions.

A fully-activated flapping foil in wind gust: Energy harvesting performance investigation

The energy harvesting performance of a fully-activated flapping foil under wind gust conditions is numerically investigated in this work. A NACA0015 airfoil performs the imposed heaving and pitching motions. The wind gust is modeled as a single frequency harmonic oscillation, and there is a phase difference between the wind gust and the pitching motion of the foil. To conduct numerical computations, the commercial code FLUENT together with the dynamic mesh strategy are adopted. At a Reynolds number of 1100 and the position of the pitching axis at one-third chord, the effects of the gust frequency, the oscillation amplitude of gust, and the phase difference between the gust and the pitch are systematically examined. By comparing with the results from the uniform flow, it is found that the energy harvesting efficiency under wind gust conditions can be changed greatly. Particularly, when the phase difference is in the range of 90° and 270°, a higher energy harvesting efficiency is produced, which is attributed to the increased lift force as well as the good synchronization between the lift force and the heaving velocity.

Observer-based Adaptive Fuzzy Backstepping Tracking Control of Quadrotor Unmanned Aerial Vehicle Powered by Li-ion Battery

In this paper, an Adaptive Fuzzy Backstepping Control (AFBC) approach with state observer is developed. This approach is used to overcome the problem of trajectory tracking for a Quadrotor Unmanned Aerial Vehicle (QUAV) under wind gust conditions and parametric uncertainties. An adaptive fuzzy controller is directly used to approximate an unknown nonlinear backstepping controller which is based on the exact model of the QUAV. Besides, a state observer is constructed to estimate the states. The stability analysis of the whole system is proved using Lyapunov direct method. Uniformly Ultimately Bounded (UUB) stability of all signals in the closed-loop system is ensured. The proposed control method guarantees the tracking of a desired trajectory, attenuates the effect of external disturbances such as wind gust, and solves the problem of unavailable states for measurement. Extended simulation studies are presented to highlight the efficiency of the proposed AFBC scheme.

Numerical study of a variable camber plunge airfoil under wind gust condition

Variable camber deformation is observed during the flight of some insects and bird species; however, the effect of this special airfoil shape motion on the aerodynamic characteristics of the airfoil is not well understood, especially for the airfoil under gust wind. We did a numerical study to investigate the aerodynamic characteristics of a variable camber plunge airfoil under wind gusts. A weak coupling program was developed to simulate the interaction between the variable camber plunge airfoil and fluid, and the flow field, aerodynamic force and energy efficiency of different camber airfoils under different wind gust conditions are investigated. It was found that camber deformation influences the aerodynamic characteristics of the airfoil greatly. If the airfoil has an appropriate camber deformation, the deformation can increase the mean thrust and the propulsive efficiency of the airfoil. Moreover, the aerodynamic characteristics of the appropriate camber airfoils are not significantly affected by the gust frequency, and there exists a range of gust amplitude where the aerodynamic characteristics of the airfoils are also not significantly affected by the gust amplitude, which may be beneficial for aerodynamic stability of the airfoil. The results also show that appropriate camber deformation can suppress leading edge vortex separation, which improves the aerodynamic characteristics of the airfoil.

The role of wing airflow sensors in bat flight control under wind gust conditions

Event Abstract Back to Event The role of wing airflow sensors in bat flight control under wind gust conditions Ben Falk1*, Delphia Varadarajan1 and Cynthia F. Moss1 1 University of Maryland, College Park, United States Insectivorous bats rely on echolocation and other sensory modalities to perform complex flight behaviors as they track flying prey and maneuver around obstacles. Microscopic hairs on the bat’s wing contribute sensory information to adaptive flight behaviors. The wing hairs are hypothesized to provide the flying bat with sensory information about air currents across the wing membrane. Neurophysiological studies have shown that bat wing hairs are directionally sensitive to airflow, and behavioral studies have shown that wing hair removal results in a decrease in the bat’s flight maneuverability (Sterbing-D’Angelo et al., PNAS, 2011). Here we report data from a behavioral study in which bats encountered gusts of wind as they performed an obstacle avoidance and prey-capture task. Echolocation signals, flight trajectories and wing kinematic data in baseline trials were compared with data in experimental trials, in which hairs were removed from the trailing and leading edges of the bat wing. Wind gusts were introduced randomly from different directions as the bat maneuvered through a narrow opening in a net to gain access to a tethered insect one meter beyond the opening. The effects of air turbulence on the bat’s flight maneuverability and echolocation behavior were quantified with high-speed video and sound recordings. By studying the effects of air turbulence on wingbeat kinematics, flight path, and echolocation behavior in bats with and without wing hairs, we hope to learn more about the mechanisms by which mammals and other organisms process sensory information to adapt their behaviors. Keywords: Adaptive Behavior, Echolocation, Flight control, multimodal signaling, navigation, sensorimotor integration Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for student poster award) Topic: Orientation and Navigation Citation: Falk B, Varadarajan D and Moss CF (2012). The role of wing airflow sensors in bat flight control under wind gust conditions. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00010 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Mr. Ben Falk, University of Maryland, College Park, College Park, United States, falk.ben@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ben Falk Delphia Varadarajan Cynthia F Moss Google Ben Falk Delphia Varadarajan Cynthia F Moss Google Scholar Ben Falk Delphia Varadarajan Cynthia F Moss PubMed Ben Falk Delphia Varadarajan Cynthia F Moss Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Dynamic Performance Enhancement of Agrid-Connected Wind Generation System

The recent trend of large wind power penetration to grid systems can be potentially troublesome in terms of dynamic performance of the system. In the absence of adequate control actions, the generators may have to be removed from the grid sometimes even for not so large changes in the wind system. This paper analyses the dynamic performance of a variable-speed wind turbine-driven cage generator connected to the grid system. It has been observed that a variable susceptance excitation controller at the generator terminals can control unusually large voltage as well as frequency swings arising from wind-gust conditions and system faults. Additional Proportional and Integral (PI) and Proportional, Integral and Derivative (PID) controls of thyristor angles in the susceptance control circuit were tested for dynamic performance improvement of the wind turbine-driven induction generator system. The variable susceptance excitation scheme with auxiliary PID control was observed to provide very good transient performance.

Operator-Mounted Controllers for Precision Tracking

This study explored the feasibility of using hand-held and leg-mounted controllers for precision tracking tasks. The hand-held device was a thumb-actuated pressure controller; the leg-mounted device was a conventional displacement stick. Two experiments were undertaken. The first was conducted in a static-based facility to explore the effects of control sensitivity and controller type on tracking performance. The second was carried out in a dynamic-motion simulator to examine the effects of buffeting on tracking, and to continue the comparison of controllers. The dynamic environment was that of a light aircraft under various wind gust conditions. Results indicated that there was no significant difference in tracking performance between the two types of controllers or the two sensitivity levels, except when a lag-lead transfer function was introduced. As expected, tracking performance was inversely related to severity of buffeting. It was concluded that either controller could be considered for use in precision tracking tasks from light aircraft subjected to light or moderate wind gust conditions.