bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wind turbine wake: bridging the gap between large eddy simulations and wind tunnel experiments
Authors: Gillyns E. , Buckingham S. , van Beeck J. , Winckelmans G. 
Published: May 2023

Abstract
The wind industry has experienced rapid growth over the past two decades and wind energy is expected to continue leading the way in the global energy transition. Additional wind farms are expected to be installed in the coming years, both offshore and onshore. In view of exploiting any suitable terrain, an increased number of turbines are installed in close proximity to existing structures, thus exposing these to the wake turbulence. For instance, electrical cables are regularly exposed to those higher levels of turbulence compared to design loads, potentially leading to premature failure of the power line. It is hence essential to have a good understanding of these phenomena to be able to mitigate their effects. Scale-resolving investigations using Large Eddy Simulation (LES) can provide insight into site-specific loading conditions when combined with an Actuator Line Model (ALM), which reproduces the reaction force of each blade on the flow while still using a relatively coarse grid. The ALM used in this framework was newly-implemented in the spectral element code Nek5000, a highly efficient code with reduced cost per degree of freedom and exponentially fast convergence. The present work aims to bridge the gap between LES and a well controlled wind tunnel test of a scaled wind turbine, for validation purposes.
First, a small scale wind turbine of diameter 80 cm is designed and tested in a well controlled wind tunnel environment. Experimental data are gathered ahead of it and in its wake, and the mean velocity and turbulence intensity profiles are presented.
Although blockage effects are kept to a minimum, they will be accounted for in the simulations to ensure a better comparison with the measurements. In this work, we focus on a single inflow velocity field and on a fixed rotation speed.
Simulating the produced wake using LES combined with ALM remains challenging as the results are very sensitive to the turbulent inflow conditions and also to the airfoil aerodynamics used in the ALM. In the experiment, the incoming profile is also that of a developing flow and accurately reproducing its main characteristics is required for proper inflow to the LES. A “Recycle and Rescale Method” (R2M) will be hence be used as it is well suited for such case. The method will allow for the relevant turbulent boundary layer structures to be properly reproduced numerically, hence ensuring that the wind turbine is exposed to similar inflow conditions than in the experiment.
With the developed framework, the comparison between the wake produced in the experiment and that obtained using LES with ALM will provide the necessary data to further adjust the parameter and grid size used for the LES and the polar model used in the ALM.
Impact of the rotor blades elasticity on the loads and wake of the large IEA 15-MW wind turbine
Authors: Trigaux Francois , Chatelain Philippe , Winckelmans Grégoire 
Published: May 2023

Abstract
This work presents an investigation of the aeroelastic effects occurring on the IEA 15-MW reference wind turbine in a turbulent atmospheric boundary layer. Large Eddy simulation is carried out using an actuator line method coupled to the finite element beam solver BeamDyn. The results show that the blades experience significant displacements, leading to an important variation of the loads along the blade span. The turbulence also interacts with the blades natural frequencies, resulting in a variation of the spectra of the various loads. The impact of the flexibility is also evaluated on the wake by comparing the undeformed configuration with a statically and dynamically deformed rotor. It appears that the mean deformation plays an important role in the wake development due to changes in the load distribution, but that the dynamic effects have minimal impact on the wake behavior.
Wake interactions behind individual-tower multi-rotor wind turbine configurations
Authors: Brown K. , Cheung L. , Hsieh A. , Maniaci D. , Hamilton W. 
Published: May 2023

Abstract
Multiple rotors on single structures have long been proposed to increase wind turbine energy capture with no increase in rotor size, but at the cost of additional mechanical complexity in the yaw and tower designs. Standard turbines on their own very-closely-spaced towers avoid these disadvantages but create a significant disadvantage; for some wind directions the wake turbulence of a rotor enters the swept area of a very close downwind rotor causing low output, fatigue stress, and changes in wake recovery. Knowing how the performance of pairs of closely spaced rotors varies with wind direction is essential to design a layout that maximizes the useful directions and minimizes the losses and stress at other directions. In the current work, the high-fidelity large-eddy simulation (LES) code Exa-Wind/Nalu-Wind is used to simulate the wake interactions from paired-rotor configurations in a neutrally stratified atmospheric boundary layer to investigate performance and feasibility. Each rotor pair consists of two Vestas V27 turbines with hub-to-hub separation distances of 1.5 rotor diameters. The on-design wind direction results are consistent with previous literature. For an off-design wind direction of 26.6°, results indicate little change in power and far-wake recovery relative to the on-design case. At a direction of 45.0°, significant rotor-wake interactions produce an increase in power but also in far-wake velocity deficit and turbulence intensity. A severely off-design case is also considered.
LiDAR Measurements to Investigate Farm-to-Farm Interactions at the AWAKEN Experiment
Authors: Puccioni Matteo , Iungo Giacomo Valerio , Moss Coleman , Solari Mojtaba Shams , Letizia Stefano , Bodini Nicola , Moriarty Patrick 
Published: May 2023

Abstract
The exponential growth of wind energy and the need to exploit wind resources over areas with higher energy potential have led to the construction of neighboring wind turbines and farms with relatively small separation distances. As a result, for specific wind and atmospheric conditions, the wakes generated by an upstream wind farm may affect wind resources available for a downstream wind farm resulting in detrimental impacts on energy harvesting and structural loads for the downwind wind turbines. Distances between neighboring wind farms are typically larger than those associated with intra-wind-farm wake interactions, generating cumulative wakes whose characteristics might differ from those predicted through classical engineering wake models. These phenomena are referred to as farm-to-farm interactions. A better understanding and characterization of farm-to-farm interactions is one of the science goals tackled by the ongoing American WAKE experimeNt (AWAKEN). The site under investigation for this field campaign comprises two large wind farms in northern Oklahoma, USA, which are spaced roughly 5km apart along the prevailing South-North wind direction. To investigate possible interactions between these two wind farms, the WindFluX mobile LiDAR station has been deployed mainly to perform volumetric scans over their gap region. In this paper, preliminary results from these LiDAR volumetric scans will be discussed, specifically for a case with multiple wind turbine wakes evolving during the occurrence of a low-level jet.
Overview of recent observations and simulations from the American WAKE experimeNt (AWAKEN) field campaign
Authors: Moriarty Patrick , Bodini Nicola , Cheung Lawrence , Hamilton Nicholas , Herges Thomas , Kaul Colleen , Letizia Stefano , Pekour Mikhail , Simley Eric 
Published: May 2023

Abstract
The American WAKE experimeNt (AWAKEN) is a large-scale field campaign focused on gathering new detailed observations of wind farm–atmosphere interactions for improved understanding of wind farm physics and overall performance. The field campaign, centered around five wind farms in northern Oklahoma, began in September 2022 and will run through at least October 2023. This paper summarizes some of the initial observations and simulations performed as part of the AWAKEN project.
Physics informed neural networks for wind field modeling in wind farms
Authors: Cobelli P. , Shukla K. , Nesmachnow S. , Draper M. 
Published: May 2023

Abstract
This article presents an approach for applying Physics-Informed Neural Networks (PINNs) for modeling wind fields in wind farms. The addressed problem is reconstructing the inflow velocity field for a wind turbine. Several PINN variants are implemented and validated over a real-world case study, trained with sparse numerically simulated velocity data. Results demonstrate that the proposed PINNs can accurately assimilate the numerical simulation data, and compute accurate solutions. The proposed approach is a viable alternative for modeling wind fields in wind farms, requiring significantly lower execution times than standard numerical/simulation methods.
Exploring cooperation between wind farms: a wake steering optimization study of the Belgian offshore wind farm cluster
Authors: Foloppe B , Dewitte L , Munters W 
Published: May 2023

Abstract
In recent years, significant research efforts have focused on increasing power extraction using wake steering through yaw misalignment. In the current work, we evaluate the potential increase in annual energy production (AEP) for the Belgian offshore wind farm cluster using the FLORIS framework. The 2.2 GW Belgian cluster is an excellent test case to explore cooperation between wind farms as the concession zone is split into nine individual farms, resulting in a mix of intra- and inter-farm wakes to be considered in one of the largest wind farm clusters operational to date. Furthermore, the cluster high power density with relatively low turbine spacings is found to be responsive to wake mitigation strategies. Three different cost functions are compared. The first one is the complete cluster yaw angles optimization. The other two are farm-based optimizations seeking to maximize either their own AEP or the cluster AEP. Results show that all wind farms benefit from every optimization, encouraging operators to implement this strategy. The cluster optimization is found to be the one providing the best AEP increase for all wind farms individually and thus for the cluster. The farm-based function optimizing the cluster AEP is in second place, encouraging wind farm operators to collaborate for their own profits.
Effect of CNTs on Dynamic Performance of Carbon Fiber Composite Boring Bar
Authors: Zhang Jinfeng , Li Ningning , Feng Chao , Zhong Peisi , Liu Tingrui 
Published: May 2023

Abstract
In this paper, through the secondary development of the finite element software ABAQUS, we try to add different contents of CNT to the CFRP composite boring bar, and establish the finite element models with different CNT contents. Firstly, on the basis of the classical laminated plate theory, combined with the composite damping loss factor model and finite element analysis method, an improved numerical model of CFRP hollow shaft damping based on inverse deviatoric transformation is adopted. Secondly, the Lanczos method was used for modal analysis, and the natural frequencies, vibration modes, stress and strain components under different fiber orientation angles (0°, 30°, 45°, 60°, 90°) and different CNT content structure constraint modes were extracted. Combined with the finite element method, the damping numerical model based on modal strain energy is established, and the damping loss factor calculation program based on strain energy is compiled by using the powerful calculation ability of MATLAB. The extracted strain component data are brought into the compiled damping loss factor calculation program, and the damping loss factors under different modes can be calculated.
Simulation Analysis of Tooth Break Faults of Gear Transmission System based on Electromagnetic Torque Signal
Authors: Yan Xiuting , Lei Fasheng , Chen Wei , Yu Xiangqian , Huang Wei 
Published: May 2023

Abstract
The traditional gear fault simulation model focuses on the vibration signal. However, the vibration sensor is not easy to install, and the vibration signal is easily affected by the installation location and environment of the vibration sensor. The motor itself has the characteristic of sensor. But in the traditional integrated model of motor and gear, the gear model is established based on the dynamical equation of the gear. However, the gear transmission established by the dynamics of the gear can’t fully reflect the running state of the gear. Moreover, the more complex the gear transmission system, the more complex and inaccurate the dynamical equation will be. Based on the above situation, in this paper, the virtual prototype model of the two-stage gear transmission system with broken tooth fault in different parts of the gear is established in Adams, which is imported into Matlab and co-simulated with the motor control model built in Matlab. Then the electromagnetic torque signal is analyzed. The results show that different characteristic frequencies of gear faults can be detected in the electromagnetic torque signal. The virtual prototype model of gear transmission system can accurately reflect the motion state of gear, and the fault of the complex gear transmission system can be simulated.
Research on the Cooling Effect of Water Injection of the Deflector on Flame of the Vertical Launch Missile
Authors: Zhang Manman , Jiang Yi , Zhang Jingli , Lei Jing , Deng Yueguang 
Published: May 2023

Abstract
The high-temperature gas generated by the missile launch will cause serious ablation to the launcher. In order to study the thermal protection of the launch device, a scheme of arranging vertical upward water spray pipes in the deflector is proposed, which realizes the thermal protection of the launcher by the vaporization and heat absorption principle of liquid water and the impact effect. Based on the Mixture multiphase flow model, coupled with the vaporization equation of liquid water and the component transport model, the cooling mechanism and effect of the proposed scheme are analyzed. Meanwhile, the numerical simulation of gas flow field under different water injection speed conditions is carried out, and the change law between different water injection speed and cooling effect is obtained. The results show that after the water sprayed by the pipes laid in the deflector, a water film will be formed on the surface of the deflector and the wall of the launch vehicle, which plays a role in the isolation of the high-temperature gas. The temperature of the launch device drops significantly. With the increase of water injection speed, the thickness of the water film formed on the surface of the deflector and the wall of the launch vehicle becomes larger, and the isolation effect on the gas becomes more obvious. When the water injection speed increases to 55m/s, the vaporization rate of liquid water in the direct impact area of the gas jet reaches the maximum, the heat absorption is the most at the same time, and the temperature in this area reaches the lowest level. The cooling effect of the water spray speed of 55m/s on the flow field is the best. This conclusion can provide a theoretical reference for the thermal protection design of missile launcher.
Numerical Simulation of the Aerodynamic Performance of A U-Shaped Sail
Authors: Tian Feng , Huang Lianzhong , Wang Yingnan , Wang Kai , Ma Ranqi 
Published: May 2023

Abstract
For a U-shaped sail that has been applied on real ships, we establish a three-dimensional sail geometry model using SolidWorks, and obtain its numerical simulation results under 10 different angles of attack using Fluent to numerically simulate its aerodynamic performance. By comparing the calculated results with the wind tunnel test results, the simulation model proved to be effective. Then the interference effects between the twin sails of the U-shaped sail were investigated by using the sail simulation model.
Study on the Efficacy of Polyethylene Filled SBMBBR Process for Treating Low Temperature Municipal Wastewater
Authors: Ding Li , Zhang Tong , Ma Xuemin , Yu Pengfei , Zhang Yanping , Fu Jinxiang 
Published: May 2023

Abstract
To tackle the hassle of low efficiency of low temperature denitrification in wintry weather in northern region,Sequencing Batch Moving Bed Biofilm Reactor (SBMBBR) used to be used for deep treatment of low temperature municipal wastewater and polyethylene fillers have been compared. The outcomes confirmed that the Sequencing Batch Activated Sludge Reactor (SBR) used to be started correctly at 64 d beneath the prerequisites of water temperature 9-12 °C,pH 7-8 and HRT of 48 h,and two polyethylene fillers had vast biofilm after 7 d operation,and the elimination rates of COD,Ammonia Nitrogen and TP in polyethylene K3 fillers have been stabilized at 83.6%,74.4% and 60.8% respectively as the quality fillers after 24 d operation. After optimizing the process parameters,the steady effluent evaluation effect used to be determined for 27 d operation beneath the most advantageous anoxic (3 h) and aerobic time (7 h) modes of the reactor,and the corresponding elimination quotes of COD and Ammonia Nitrogen were 87.7% and 93.5%,respectively,and the corresponding average effluent concentrations had been 44.4 mg/L and 1.9 mg/L,which reached the Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB 18918-2002). Two vital factors,Dissolved Oxygen (DO) concentration and Hydraulic retention time (HRT) in the aerobic part were studied,and the great HRT of 82 h was once performed in the biointensive domestication SBR machine under the stipulations of the foremost vary of DO attention of 6.0-7.5 mg/L in the aerobic part at low water temperature.
Moving Object Detection Based on Ghost and Shadow Removal
Authors: Zhou Dan , Liu Ying , Li Ke 
Published: May 2023

Abstract
With the rapid development of information technology and the popularization of security awareness, the society’s demand for intelligent video surveillance is higher and higher. As a key step, moving object detection with a long history of research and continuously changed research methods has become a frontier topic in various disciplines. Aiming at the removal of ghosts, this paper proposes an improved visual background extractor algorithm (Vibe), and then combines texture information to remove shadows which can achieve the purpose of removing heavy shadows and ghosts. Finally, achieving a good video moving target detection.
Automatic Geographic Information Classification Method Based on SVM for Site Selection of Stretch Field
Authors: Jing Wenchuan , Qiang Wang , Yang Jian , Wang Tao , Li Gang 
Published: May 2023

Abstract
In tension stringing construction, the site selection of the stretch field is related to the efficiency, safety and cost of the whole wire construction. Surrounding geographic information impacts the site selection extremely seriously. Accurate grasp of the surrounding geographic information along the transmission line is the key to ensure the optimal site selection of the stretch field. Aiming at the geographic image data along the transmission lines collected by the UAV, firstly, the map data is blocked using the image gradient information and the geometric topological relationship in the image; then, the histogram features of the gradient direction are extracted from the blocked data; finally, the support vector machine is used to train the extracted features, and the map data is classified according to the model obtained from the training, and finally the automatic classification and recognition of the geographic information along the transmission lines is obtained. The proposed method can achieve high recognition accuracy by using small samples for training. Through practice, the proposed method can accurately classify map data, thus providing a reliable guarantee for determining the surrounding geographic influences when selecting a site for a stretch field.
Estimation of the optimal number of neurons in extreme learning machine using simulated annealing and the golden section
Authors: Gelvez-Almeida E , Mora M , Huérfano-Maldonado Y , Salazar-Jurado E , Martínez-Jeraldo N , Lozada-Yavina R , Baldera-Moreno Y , Tobar L 
Published: June 2023

Abstract
Extreme learning machine is a neural network algorithm widely accepted in the scientific community due to the simplicity of the model and its good results in classification and regression problems; digital image processing, medical diagnosis, and signal recognition are some applications in the field of physics addressed with these neural networks. The algorithm must be executed with an adequate number of neurons in the hidden layer to obtain good results. Identifying the appropriate number of neurons in the hidden layer is an open problem in the extreme learning machine field. The search process has a high computational cost if carried out sequentially, given the complexity of the calculations as the number of neurons increases. In this work, we use the search of the golden section and simulated annealing as heuristic methods to calculate the appropriate number of neurons in the hidden layer of an Extreme Learning Machine; for the experiments, three real databases were used for the classification problem and a synthetic database for the regression problem. The results show that the search for the appropriate number of neurons is accelerated up to 4.5× times with simulated annealing and up to 95.7× times with the golden section search compared to a sequential method in the highest-dimensional database.
Analysis of the stresses for a bridge by the finite element method under the action of viscous damping
Authors: Oñate Ballesteros R D , Balcázar L A , Navarro A , Ospina Henao P A 
Published: June 2023

Abstract
Specifically speaking of the treatment of constructions (such as bridges), the importance of considering dynamic phenomena from the design phase lies in the fact that the protection of the construction against unwanted external disturbances, such as those produced by earthquakes and vehicle traffic, is guaranteed. automotive, among other causes, that may cause partial or total damage to the structure. As a tool, we have computer-aided design and engineering for the structuring of mechanical designs, which adds efficiency to detect design errors in early phases. The relevance of this project lies in the application of knowledge to the areas of computer-aided design in civil structures such as bridges, through computerized simulation in CSI Bridge and mathematical analysis to determine the efforts and graphically observe the behavior of the bridge when subjected to viscous damping. The physical relevance of this project lies in the application of knowledge to the design areas of civil structures such as bridges, through computerized simulation and mathematical and physical analysis to determine the efforts and graphically observe the behavior of the bridge when it is subjected to external disturbances that act as viscous damping. Physically, we model this damping as a friction force in general to solve the equation using numerical methods by changing different boundary conditions in the damping factor, which adds relevance to the computational modeling of the bridge and the study of its physical and mechanical properties.