Advanced Model Initialization Techniques

Large-eddy simulation (LES) with actuator models has become the state-of-the-art numerical tool to study the complex interaction between the atmospheric boundary layer (ABL) and wind turbines. In this paper, a new evaluation of actuator disk models (ADMs) for LES of wind turbine flows is presented. Several details of the implementation of such models are evaluated based on a test case studied experimentally. In contrast to other test cases used in previous similar studies, the present test case consists of a wind turbine immersed in a realistic turbulent boundary-layer flow, for which accurate data for the turbine, the flow, the thrust and the power are available. It is found that the projection of the forces generated by the turbine into the flow solver grid is crucial for rotor predictions, especially for the power, and less important for the wake flow prediction. In this context, the projection of the forces into the flow solver grid should be as accurate as possible, in order to conserve the consistency between the computed axial velocity and the projected axial force. Also, the projection of the force is found to be much more important in the rotor plane directions than in the streamwise direction. It is found that for the case of a wind turbine immersed in a realistic turbulent boundary-layer flow, the potential spurious numerical oscillations originating from sharp force projections are not harmful to the results. By comparing an advanced model which computes the non-uniform distribution of the turbine forces over the rotor with a simple model which assumes uniform effects of the turbine forces, it is found that both can lead to accurate results for the far wake flow and the thrust and power predictions. However, the comparison shows that the advanced model leads to better results for the near wake flow. In addition, it is found that the simple model overestimates the rotor velocity prediction in comparison to the advanced model. These elements are explained by the lack of local feedback between the axial velocity and the axial force in the simple model. By comparing simulations with and without including the effects of the nacelle and tower, it is found that the consideration of the nacelle and tower is relatively important both for the near wake and the power prediction, due to the shadow effects. The grid resolution is not found to be critical once a reasonable resolution is used, i.e. in the order of 10 grid points along each direction across the rotor. The comparison with the experimental data shows that an accurate prediction of the flow, thrust, and power is possible with a very reasonable computational cost. Overall, the results give important guidelines for the implementation of ADMs for LES.

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RTEAM: Risk-Based Trust Evaluation Advanced Model for VANETs

IEEE Access ◽

10.1109/access.2021.3107467 ◽

2021 ◽

Vol 9 ◽

pp. 117772-117783

Author(s):

Rasha Jamal Atwa ◽

Paola Flocchini ◽

Amiya Nayak

Keyword(s):

Trust Evaluation ◽

Advanced Model

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Understanding the Processes Causing the Early Intensification of Hurricane Dorian through an Ensemble of the Hurricane Analysis and Forecast System (HAFS)

Atmosphere ◽

10.3390/atmos12010093 ◽

2021 ◽

Vol 12 (1) ◽

pp. 93

Author(s):

Andrew Hazelton ◽

Ghassan J. Alaka ◽

Levi Cowan ◽

Michael Fischer ◽

Sundararaman Gopalakrishnan

Keyword(s):

Tropical Cyclone ◽

Large Scale ◽

Early Stage ◽

Early Period ◽

Storm Track ◽

Key Factors ◽

Complex Interplay ◽

Forecast System ◽

Model Initialization

The early stages of a tropical cyclone can be a challenge to forecast, as a storm consolidates and begins to grow based on the local and environmental conditions. A high-resolution ensemble of the Hurricane Analysis and Forecast System (HAFS) is used to study the early intensification of Hurricane Dorian, a catastrophic 2019 storm in which the early period proved challenging for forecasters. There was a clear connection in the ensemble between early storm track and intensity: stronger members moved more northeast initially, although this result did not have much impact on the long-term track. The ensemble results show several key factors determining the early evolution of Dorian. Large-scale divergence northeast of the tropical cyclone (TC) appeared to favor intensification, and this structure was present at model initialization. There was also greater moisture northeast of the TC for stronger members at initialization, favoring more intensification and downshear development of the circulation as these members evolved. This study highlights the complex interplay between synoptic and storm scale processes in the development and intensification of early-stage tropical cyclones.

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Research on Ground Subsidence in Shield Tunneling Construction in Advanced Model

ICPTT 2013 ◽

10.1061/9780784413142.070 ◽

2013 ◽

Author(s):

Yeqin Zhang ◽

Huagang He ◽

Hui Zhao

Keyword(s):

Ground Subsidence ◽

Shield Tunneling ◽

Advanced Model

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Application of Advanced Model of Zr-Based Cladding Oxidation in Steam-Oxygen-Nitrogen Gas Mixtures to Separate Effects Tests and Integral Experiments

Volume 6B: Energy ◽

10.1115/imece2015-53209 ◽

2015 ◽

Author(s):

Alexander Vasiliev

Keyword(s):

Diffusion Coefficient ◽

Nuclear Power ◽

Temperature Oxidation ◽

Parabolic Kinetics ◽

Design Basis ◽

Design Basis Accident ◽

Air Ingress ◽

Pure Steam ◽

Modeling Code ◽

Advanced Model

During postulated design-basis or beyond-design-basis accident at nuclear power plant with PWR or BWR, the high temperature oxidation of Zr-based fuel claddings in H2O-O2-N2 gas atmosphere could take place. Recent experimental observations showed that the oxidation of those claddings in the air (or, more generally, in oxygen-nitrogen and steam-nitrogen mixtures) behaves in much more aggressive way (linear or enhanced parabolic kinetics) compared to oxidation in pure steam (standard parabolic kinetics). This is why an advanced model of Zr-based cladding oxidation was developed. For calculations of cladding oxidation in oxygen-nitrogen and steam-nitrogen mixtures, the effective oxygen diffusion coefficient in ZrO2+ZrN layer formed in cladding is used. The diffusion coefficient enhancement factor depends on ZrN content in ZrO2+ZrN layer. A numerical scheme was realized to determine ZrO2+ZrN/α-Zr(O) and α-Zr(O)/β-Zr layers boundaries relocation and layers transformations in claddings. The model was implemented to the SOCRAT best estimate computer modeling code. The SOCRAT code with advanced model of oxidation was successfully used for calculations of separate effects tests and air ingress integral experiments QUENCH-10, QUENCH-16 and PARAMETER-SF4.

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Power Quality: Scientific Collaboration Networks and Research Trends

Energies ◽

10.3390/en11082067 ◽

2018 ◽

Vol 11 (8) ◽

pp. 2067 ◽

Cited By ~ 13

Author(s):

Francisco Montoya ◽

Raul Baños ◽

Alfredo Alcayde ◽

Maria Montoya ◽

Francisco Manzano-Agugliaro

Keyword(s):

Power Quality ◽

Scientific Collaboration ◽

Research Field ◽

Research Trends ◽

Collaboration Network ◽

Collaboration Networks ◽

Different Types ◽

Voltage Frequency ◽

Advanced Model ◽

Proper Operation

Power quality is a research field related to the proper operation of devices and technological equipment in industry, service, and domestic activities. The level of power quality is determined by variations in voltage, frequency, and waveforms with respect to reference values. These variations correspond to different types of disturbances, including power fluctuations, interruptions, and transients. Several studies have been focused on analysing power quality issues. However, there is a lack of studies on the analysis of both the trending topics and the scientific collaboration network underlying the field of power quality. To address these aspects, an advanced model is used to retrieve data from publications related to power quality and analyse this information using a graph visualisation software and statistical tools. The results suggest that research interests are mainly focused on the analysis of power quality problems and mitigation techniques. Furthermore, they are observed important collaboration networks between researchers within and across countries.

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Modeling of electrical characteristics of photo voltaic and effecting of cell parameters on V-I curve

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i2.13.12680 ◽

2018 ◽

Vol 7 (2.13) ◽

pp. 276 ◽

Cited By ~ 1

Author(s):

Fawaz S. Abdullah ◽

Safwan A. Hamoodi ◽

Ali N. Hamoodi

Keyword(s):

Current Flow ◽

Current Source ◽

Accurate Information ◽

Electrical Characteristics ◽

Solar Pv ◽

Cell Parameters ◽

Pv Systems ◽

Photo Voltaic ◽

Series Resistor ◽

Advanced Model

Studding of PV systems in an active way needs accurate information of the power and voltage P-V current and voltage I-V characteristic curves of solar PV order. Therefore, this paper shows emulation of solar PV model utilizes Matlab/Simulink and practical results. This PV model depends on math’s equation and is explained during an equivalent circuit involving a photo current source, diode, shunt resistor and series resistor representing leakage current and series resistor expressing the inside losses because of the current flow. The advanced model let the prognosis of PV array manner under various circuit model and ecological parameters solar temperature, ray. A special model (Lcs M200 – JA/SI) solar collector using for this paper, results was compared with practical curve with different points of the curve and show good conformity to the model.

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Improvement in Surface Solar Irradiance Estimation Using HRV/MSG Data

Remote Sensing ◽

10.3390/rs10081288 ◽

2018 ◽

Vol 10 (8) ◽

pp. 1288 ◽

Cited By ~ 12

Author(s):

Filomena Romano ◽

Domenico Cimini ◽

Angela Cersosimo ◽

Francesco Di Paola ◽

Donatello Gallucci ◽

...

Keyword(s):

High Resolution ◽

Solar Irradiance ◽

Research Council ◽

National Research Council ◽

The Other ◽

Data Channel ◽

The Difference ◽

Photovoltaic Plants ◽

Sky Conditions ◽

Advanced Model

The Advanced Model for the Estimation of Surface Solar Irradiance (AMESIS) was developed at the Institute of Methodologies for Environmental Analysis of the National Research Council of Italy (IMAA-CNR) to derive surface solar irradiance from SEVIRI radiometer on board the MSG geostationary satellite. The operational version of AMESIS has been running continuously at IMAA-CNR over all of Italy since 2017 in support to the monitoring of photovoltaic plants. The AMESIS operative model provides two different estimations of the surface solar irradiance: one is obtained considering only the low-resolution channels (SSI_VIS), while the other also takes into account the high-resolution HRV channel (SSI_HRV). This paper shows the difference between these two products against simultaneous ground-based observations from a network of 63 pyranometers for different sky conditions (clear, overcast and partially cloudy). Comparable statistical scores have been obtained for both AMESIS products in clear and cloud situation. In terms of bias and correlation coefficient over partially cloudy sky, better performances are found for SSI_HRV (0.34 W/m2 and 0.995, respectively) than SSI_VIS (−33.69 W/m2 and 0.862) at the expense of the greater run-time necessary to process HRV data channel.

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