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Prof. Unai Fernandez-Gamiz
University of the Basque Country (UPV-EHU)

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Research Keywords & Expertise

0 CFD modeling
0 Turbulence Modeling
0 Fluid Mechanics
0 aerodynamic
0 wind turbine engineering

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Journal article
Published: 24 August 2021 in Symmetry
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In this study, a water reattachment length was calculated by adopting two different models. The first was based on Unsteady Reynolds-Averaged Navier–Stokes (URANS) k-omega with Shear Stress Transport (SST); the second was a Large Eddy Simulation (LES) with Wall-Adapting Local Eddy-Viscosity (WALE). Both models used the same mesh and were checked with Taylor length-scale analysis. After the analysis, the mesh had 11,040,000 hexahedral cells. The geometry was a symmetrical expansion–contraction tube with a 4.28 expansion ratio that created mechanical energy losses, which were taken into account. Moreover, the reattachment length was estimated by analyzing the speed values; the change of speed value from negative to positive was used as the criterion to recognize the reattachment point.

ACS Style

Daniel Teso-Fz-Betoño; Martin Juica; Koldo Portal-Porras; Unai Fernandez-Gamiz; Ekaitz Zulueta. Estimating the Reattachment Length by Realizing a Comparison between URANS k-Omega SST and LES WALE Models on a Symmetric Geometry. Symmetry 2021, 13, 1555 .

AMA Style

Daniel Teso-Fz-Betoño, Martin Juica, Koldo Portal-Porras, Unai Fernandez-Gamiz, Ekaitz Zulueta. Estimating the Reattachment Length by Realizing a Comparison between URANS k-Omega SST and LES WALE Models on a Symmetric Geometry. Symmetry. 2021; 13 (9):1555.

Chicago/Turabian Style

Daniel Teso-Fz-Betoño; Martin Juica; Koldo Portal-Porras; Unai Fernandez-Gamiz; Ekaitz Zulueta. 2021. "Estimating the Reattachment Length by Realizing a Comparison between URANS k-Omega SST and LES WALE Models on a Symmetric Geometry." Symmetry 13, no. 9: 1555.

Journal article
Published: 14 August 2021 in Sustainability
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Flow control device modeling is an engaging research field for wind turbine optimization, since in recent years wind turbines have grown in proportions and weight. The purpose of the present work was to study the performance and effects generated by a rotating microtab (MT) implemented on the trailing edge of a DU91W250 airfoil through the novel cell-set (CS) model for the first time via CFD techniques. The CS method is based on the reutilization of an already calculated mesh for the addition of new geometries on it. To accomplish that objective, the required region is split from the main domain, and new boundaries are assigned to the mentioned construction. Three different MT lengths were considered: h = 1%, 1.5% and 2% of the airfoil chord length, as well as seven MT orientations (β): from 0° to −90° regarding the horizontal axis, for five angles of attack: 0°, 2°, 4°, 6° and 9°. The numerical results showed that the increases of the β rotating angle and the MT length (h) led to higher aerodynamic performance of the airfoil, CL/CD = 164.10 being the maximum ratio obtained. All the performance curves showed an asymptotic trend as the β angle reduced. Qualitatively, the model behaved as expected, proving the relationship between velocity and pressure. Taking into consideration resulting data, the cell-set method is appropriate for computational testing of trailing edge rotating microtab geometry.

ACS Style

Alejandro Ballesteros-Coll; Koldo Portal-Porras; Unai Fernandez-Gamiz; Ekaitz Zulueta; Jose Manuel Lopez-Guede. Rotating Microtab Implementation on a DU91W250 Airfoil Based on the Cell-Set Model. Sustainability 2021, 13, 9114 .

AMA Style

Alejandro Ballesteros-Coll, Koldo Portal-Porras, Unai Fernandez-Gamiz, Ekaitz Zulueta, Jose Manuel Lopez-Guede. Rotating Microtab Implementation on a DU91W250 Airfoil Based on the Cell-Set Model. Sustainability. 2021; 13 (16):9114.

Chicago/Turabian Style

Alejandro Ballesteros-Coll; Koldo Portal-Porras; Unai Fernandez-Gamiz; Ekaitz Zulueta; Jose Manuel Lopez-Guede. 2021. "Rotating Microtab Implementation on a DU91W250 Airfoil Based on the Cell-Set Model." Sustainability 13, no. 16: 9114.

Journal article
Published: 14 August 2021 in Mathematics
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Turbulence in fluids has been a popular research topic for many years due to its influence on a wide range of applications. Computational Fluid Dynamics (CFD) tools are able to provide plenty of information about this phenomenon, but their computational cost often makes the use of these tools unfeasible. For that reason, in recent years, turbulence modelling using Artificial Neural Networks (ANNs) is becoming increasingly popular. These networks typically calculate directly the desired magnitude, having input information about the computational domain. In this paper, a Convolutional Neural Network (CNN) for predicting different magnitudes of turbulent flows around different geometries by approximating the equations of the Reynolds-Averaged Navier-Stokes (RANS)-based realizable k-ε two-layer turbulence model is proposed. Using that CNN, alternative network structures are proposed to predict the velocity fields of a turbulent flow around different geometries on a rectangular channel, with a preliminary stage to predict pressure and vorticity fields before calculating the velocity fields, and the obtained results are compared with the ones obtained with the basic structure. The results demonstrate that the proposed structures clearly outperform the basic one, especially when the flow becomes uncertain. In addition, considering the results, the best network configuration is proposed. That network is tested with a domain with multiple geometries and a domain with a narrowing of the channel, which are domains with different conditions from the training ones, showing fairly accurate predictions.

ACS Style

Koldo Portal-Porras; Unai Fernandez-Gamiz; Ainara Ugarte-Anero; Ekaitz Zulueta; Asier Zulueta. Alternative Artificial Neural Network Structures for Turbulent Flow Velocity Field Prediction. Mathematics 2021, 9, 1939 .

AMA Style

Koldo Portal-Porras, Unai Fernandez-Gamiz, Ainara Ugarte-Anero, Ekaitz Zulueta, Asier Zulueta. Alternative Artificial Neural Network Structures for Turbulent Flow Velocity Field Prediction. Mathematics. 2021; 9 (16):1939.

Chicago/Turabian Style

Koldo Portal-Porras; Unai Fernandez-Gamiz; Ainara Ugarte-Anero; Ekaitz Zulueta; Asier Zulueta. 2021. "Alternative Artificial Neural Network Structures for Turbulent Flow Velocity Field Prediction." Mathematics 9, no. 16: 1939.

Journal article
Published: 04 August 2021 in Mathematics
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The computational cost and memory demand required by computational fluid dynamics (CFD) codes simulations can become very high. Therefore, the application of convolutional neural networks (CNN) in this field has been studied owing to its capacity to learn patterns from sets of input data, which can considerably approximate the results of the CFD simulations with relative low errors. DeepCFD code has been taken as a basis and with some slight variations in the parameters of the CNN, while the net is able to solve the Navier–Stokes equations for steady turbulent flows with variable input velocities to the domain. In order to acquire extensive input data to the CNN, a data augmentation technique, which considers the similarity principle for fluid dynamics, is implemented. As a consequence, DeepCFD is able to learn the velocities and pressure fields quite accurately, speeding up the time-consuming CFD simulations.

ACS Style

Alvaro Abucide-Armas; Koldo Portal-Porras; Unai Fernandez-Gamiz; Ekaitz Zulueta; Adrian Teso-Fz-Betoño. A Data Augmentation-Based Technique for Deep Learning Applied to CFD Simulations. Mathematics 2021, 9, 1843 .

AMA Style

Alvaro Abucide-Armas, Koldo Portal-Porras, Unai Fernandez-Gamiz, Ekaitz Zulueta, Adrian Teso-Fz-Betoño. A Data Augmentation-Based Technique for Deep Learning Applied to CFD Simulations. Mathematics. 2021; 9 (16):1843.

Chicago/Turabian Style

Alvaro Abucide-Armas; Koldo Portal-Porras; Unai Fernandez-Gamiz; Ekaitz Zulueta; Adrian Teso-Fz-Betoño. 2021. "A Data Augmentation-Based Technique for Deep Learning Applied to CFD Simulations." Mathematics 9, no. 16: 1843.

Journal article
Published: 05 July 2021 in Mathematics
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The protection provided by wearing masks has been a guideline worldwide to prevent the risk of COVID-19 infection. The current work presents an investigation that analyzes the effectiveness of face shields as personal protective equipment. To that end, a multiphase computational fluid dynamic study based on Eulerian–Lagrangian techniques was defined to simulate the spread of the droplets produced by a sneeze. Different scenarios were evaluated where the relative humidity, ambient temperature, evaporation, mass transfer, break up, and turbulent dispersion were taken into account. The saliva that the human body generates was modeled as a saline solution of 8.8 g per 100 mL. In addition, the influence of the wind speed was studied with a soft breeze of 7 km/h and a moderate wind of 14 km/h. The results indicate that the face shield does not provide accurate protection, because only the person who is sneezed on is protected. Moreover, with a wind of 14 km/h, none of the droplets exhaled into the environment hit the face shield, instead, they were deposited onto the neck and face of the wearer. In the presence of an airflow, the droplets exhaled into the environment exceeded the safe distance marked by the WHO. Relative humidity and ambient temperature play an important role in the lifetime of the droplets.

ACS Style

Ainara Ugarte-Anero; Unai Fernandez-Gamiz; Iñigo Aramendia; Ekaitz Zulueta; Jose Lopez-Guede. Numerical Modeling of Face Shield Protection against a Sneeze. Mathematics 2021, 9, 1582 .

AMA Style

Ainara Ugarte-Anero, Unai Fernandez-Gamiz, Iñigo Aramendia, Ekaitz Zulueta, Jose Lopez-Guede. Numerical Modeling of Face Shield Protection against a Sneeze. Mathematics. 2021; 9 (13):1582.

Chicago/Turabian Style

Ainara Ugarte-Anero; Unai Fernandez-Gamiz; Iñigo Aramendia; Ekaitz Zulueta; Jose Lopez-Guede. 2021. "Numerical Modeling of Face Shield Protection against a Sneeze." Mathematics 9, no. 13: 1582.

Journal article
Published: 06 June 2021 in Electronics
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Obtaining tools to analyze and predict the performance of batteries is a non-trivial challenge because it involves non-destructive evaluation procedures. At the research level, the development of sensors to allow cell-level monitoring is an innovative path, and electrochemical impedance spectrometry (EIS) has been identified as one of the most promising tools, as is the generation of advanced multivariable models that integrate environmental and internal-battery information. In this article, we describe an algorithm that automatically identifies a battery-equivalent electrochemical model based on electroscopic impedance data. This algorithm allows in operando monitoring of variations in the equivalent circuit parameters that will be used to further estimate variations in the state of health (SoH) and state of charge (SoC) of the battery based on a correlation with experimental aging data corresponding to states of failure or degradation. In the current work, the authors propose a two-step parameter identification algorithm. The first consists of a rough differential evolution algorithm-based identification. The second is based on the Nelder–Mead Simplex search method, which gives a fine parameter estimation. These algorithm results were compared with those of the commercially available Z-view, an equivalent circuit tool estimation that requires expert human input.

ACS Style

Javier Olarte; Jaione Martínez de Ilarduya; Ekaitz Zulueta; Raquel Ferret; Unai Fernández-Gámiz; Jose Lopez-Guede. Automatic Identification Algorithm of Equivalent Electrochemical Circuit Based on Electroscopic Impedance Data for a Lead Acid Battery. Electronics 2021, 10, 1353 .

AMA Style

Javier Olarte, Jaione Martínez de Ilarduya, Ekaitz Zulueta, Raquel Ferret, Unai Fernández-Gámiz, Jose Lopez-Guede. Automatic Identification Algorithm of Equivalent Electrochemical Circuit Based on Electroscopic Impedance Data for a Lead Acid Battery. Electronics. 2021; 10 (11):1353.

Chicago/Turabian Style

Javier Olarte; Jaione Martínez de Ilarduya; Ekaitz Zulueta; Raquel Ferret; Unai Fernández-Gámiz; Jose Lopez-Guede. 2021. "Automatic Identification Algorithm of Equivalent Electrochemical Circuit Based on Electroscopic Impedance Data for a Lead Acid Battery." Electronics 10, no. 11: 1353.

Journal article
Published: 21 May 2021 in Electronics
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This work presents a battery management system for lead–acid batteries that integrates a battery-block (12 V) sensor that allows the online monitoring of a cell’s temperature, voltage, and impedance spectra. The monitoring and diagnostic capabilities enable the implementation of improved battery management algorithms in order to increase the life expectancy of lead–acid batteries and report the battery health conditions. The novelty is based on the online monitoring of the evolution of electrochemical impedance spectroscopy (EIS) over a battery’s life as a way to monitor the battery’s performance. Active cell balancing is also proposed as an alternative to traditional charge equalization to minimize excessive electrolyte consumption. A battery-block sensor (VTZ) was validated by using the correlation between experimental data collected from electrochemical impedance spectroscopy lab-testing equipment and sensors that were implemented in a series of 12 V lead–acid battery blocks. The modular design and small size allow easy and direct integration into different commercial cell formats, and the proposed methodology can be used for applications ranging from automotive to stationary energy storage.

ACS Style

Javier Olarte; Jaione Martínez de Ilarduya; Ekaitz Zulueta; Raquel Ferret; Unai Fernández-Gámiz; Jose Lopez-Guede. A Battery Management System with EIS Monitoring of Life Expectancy for Lead–Acid Batteries. Electronics 2021, 10, 1228 .

AMA Style

Javier Olarte, Jaione Martínez de Ilarduya, Ekaitz Zulueta, Raquel Ferret, Unai Fernández-Gámiz, Jose Lopez-Guede. A Battery Management System with EIS Monitoring of Life Expectancy for Lead–Acid Batteries. Electronics. 2021; 10 (11):1228.

Chicago/Turabian Style

Javier Olarte; Jaione Martínez de Ilarduya; Ekaitz Zulueta; Raquel Ferret; Unai Fernández-Gámiz; Jose Lopez-Guede. 2021. "A Battery Management System with EIS Monitoring of Life Expectancy for Lead–Acid Batteries." Electronics 10, no. 11: 1228.

Journal article
Published: 19 May 2021 in International Journal of Environmental Research and Public Health
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The COVID-19 pandemic has pointed to the need to increase our knowledge in fields related to human breathing. In the present study, temperature, relative humidity, carbon dioxide (CO2) concentration, and median particle size diameter measurements were taken into account. These parameters were analyzed in a computer classroom with 15 subjects during a normal 90-minute class; all the subjects wore surgical masks. For measurements, Arduino YUN, Arduino UNO, and APS-3321 devices were used. Natural ventilation efficiency was checked in two different ventilation scenarios: only windows open and windows and doors open. The results show how ventilation affects the temperature, CO2 concentration, and median particle diameter size parameters. By contrast, the relative humidity depends more on the outdoor meteorological conditions. Both ventilation scenarios tend to create the same room conditions in terms of temperature, humidity, CO2 concentration, and particle size. Additionally, the evolution of CO2 concentration as well as the particle size distribution along the time was studied. Finally, the particulate matter (PM2.5) was investigated together with particle concentration. Both parameters showed a similar trend during the time of the experiments.

ACS Style

Sergio Chillon; Mikel Millan; Iñigo Aramendia; Unai Fernandez-Gamiz; Ekaitz Zulueta; Xabier Mendaza-Sagastizabal. Natural Ventilation Characterization in a Classroom under Different Scenarios. International Journal of Environmental Research and Public Health 2021, 18, 5425 .

AMA Style

Sergio Chillon, Mikel Millan, Iñigo Aramendia, Unai Fernandez-Gamiz, Ekaitz Zulueta, Xabier Mendaza-Sagastizabal. Natural Ventilation Characterization in a Classroom under Different Scenarios. International Journal of Environmental Research and Public Health. 2021; 18 (10):5425.

Chicago/Turabian Style

Sergio Chillon; Mikel Millan; Iñigo Aramendia; Unai Fernandez-Gamiz; Ekaitz Zulueta; Xabier Mendaza-Sagastizabal. 2021. "Natural Ventilation Characterization in a Classroom under Different Scenarios." International Journal of Environmental Research and Public Health 18, no. 10: 5425.

Chapter
Published: 23 March 2021 in Numerical Methods for Energy Applications
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The design procedure of a Machine Learning (ML) based yaw control strategy for a Horizontal Axis Wind Turbine (HAWT) is presented in the following chapter. The proposed yaw control strategy is based on the interaction of three different Artificial Intelligence (AI) techniques to design a ML system: Reinforcement Learning (RL), Artificial Neural Networks (ANN) and metaheuristic optimization algorithms. The objective of the designed control strategy is to achieve, after a training stage, a fully autonomous performance of the wind turbine yaw control system for different input wind scenarios while optimizing the electrical power generated by the wind turbine and the mechanical loads due to the yaw rotation. The RL algorithm is known to be able to learn from experience. The training process could be carried out online with real-time data of the operation of the wind turbine or offline, with simulation data. The use of an ANN to store the data of the matrix Q(s, a) related to the RL algorithm eliminates the large scale data management and simplifies the operation of the proposed control system. Finally, the implementation of a metaheuristic optimization algorithm, in this case a Particle Swarm Optimization (PSO) algorithm, allows calculation of the optimal yaw control action that responds to the compromise between the generated power increment and the mechanical loads increase due to the yaw actuation.

ACS Style

Aitor Saenz-Aguirre; Ekaitz Zulueta; Unai Fernandez-Gamiz; Jose Antonio Ramos-Hernanz; Jose Manuel Lopez-Guede. Self-tuning Yaw Control Strategy of a Horizontal Axis Wind Turbine Based on Machine Learning. Numerical Methods for Energy Applications 2021, 879 -900.

AMA Style

Aitor Saenz-Aguirre, Ekaitz Zulueta, Unai Fernandez-Gamiz, Jose Antonio Ramos-Hernanz, Jose Manuel Lopez-Guede. Self-tuning Yaw Control Strategy of a Horizontal Axis Wind Turbine Based on Machine Learning. Numerical Methods for Energy Applications. 2021; ():879-900.

Chicago/Turabian Style

Aitor Saenz-Aguirre; Ekaitz Zulueta; Unai Fernandez-Gamiz; Jose Antonio Ramos-Hernanz; Jose Manuel Lopez-Guede. 2021. "Self-tuning Yaw Control Strategy of a Horizontal Axis Wind Turbine Based on Machine Learning." Numerical Methods for Energy Applications , no. : 879-900.

Journal article
Published: 11 March 2021 in Processes
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Vortex Generators (VGs) are applied before the expected region of separation of the boundary layer in order to delay or remove the flow separation. Although their height is usually similar to that of the boundary layer, in some applications, lower VGs are used, Sub-Boundary Layer Vortex Generators (SBVGs), since this reduces the drag coefficient. Numerical simulations of sub-boundary layer vane-type vortex generators on a flat plate in a negligible pressure gradient flow were conducted using the fully resolved mesh model and the cell-set model, with the aim on assessing the accuracy of the cell-set model with Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) turbulence modelling techniques. The implementation of the cell-set model has supposed savings of the 40% in terms of computational time. The vortexes generated on the wake behind the VG; vortical structure of the primary vortex; and its path, size, strength, and produced wall shear stress have been studied. The results show good agreements between meshing models in the higher VGs, but slight discrepancies on the lower ones. These disparities are more pronounced with LES. Further study of the cell-set model is proposed, since its implementation entails great computational time and resources savings.

ACS Style

Koldo Portal-Porras; Unai Fernandez-Gamiz; Iñigo Aramendia; Daniel Teso-Fz-Betoño; Ekaitz Zulueta. Testing the Accuracy of the Cell-Set Model Applied on Vane-Type Sub-Boundary Layer Vortex Generators. Processes 2021, 9, 503 .

AMA Style

Koldo Portal-Porras, Unai Fernandez-Gamiz, Iñigo Aramendia, Daniel Teso-Fz-Betoño, Ekaitz Zulueta. Testing the Accuracy of the Cell-Set Model Applied on Vane-Type Sub-Boundary Layer Vortex Generators. Processes. 2021; 9 (3):503.

Chicago/Turabian Style

Koldo Portal-Porras; Unai Fernandez-Gamiz; Iñigo Aramendia; Daniel Teso-Fz-Betoño; Ekaitz Zulueta. 2021. "Testing the Accuracy of the Cell-Set Model Applied on Vane-Type Sub-Boundary Layer Vortex Generators." Processes 9, no. 3: 503.

Journal article
Published: 08 March 2021 in Mathematics
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The coronavirus disease 2019 (COVID-19) outbreak has altered the lives of everyone on a global scale due to its high transmission rate. In the current work, the droplet dispersion and evaporation originated by a cough at different velocities is studied. A multiphase computational fluid dynamic model based on fully coupled Eulerian–Lagrangian techniques was used. The evaporation, breakup, mass transfer, phase change, and turbulent dispersion forces of droplets were taken into account. A computational domain imitating an elevator that with two individuals inside was modeled. The results showed that all droplets smaller than 150 μm evaporate before 10 s at different heights. Smaller droplets of <30 µm evaporate quickly, and their trajectories are governed by Brownian movements. Instead, the trajectories of medium-sized droplets (30–80 µm) are under the influence of inertial forces, while bigger droplets move according to inertial and gravitational forces. Smaller droplets are located in the top positions, while larger (i.e., heaviest) droplets are located at the bottom.

ACS Style

Sergio Chillón; Ainara Ugarte-Anero; Iñigo Aramendia; Unai Fernandez-Gamiz; Ekaitz Zulueta. Numerical Modeling of the Spread of Cough Saliva Droplets in a Calm Confined Space. Mathematics 2021, 9, 574 .

AMA Style

Sergio Chillón, Ainara Ugarte-Anero, Iñigo Aramendia, Unai Fernandez-Gamiz, Ekaitz Zulueta. Numerical Modeling of the Spread of Cough Saliva Droplets in a Calm Confined Space. Mathematics. 2021; 9 (5):574.

Chicago/Turabian Style

Sergio Chillón; Ainara Ugarte-Anero; Iñigo Aramendia; Unai Fernandez-Gamiz; Ekaitz Zulueta. 2021. "Numerical Modeling of the Spread of Cough Saliva Droplets in a Calm Confined Space." Mathematics 9, no. 5: 574.

Journal article
Published: 21 February 2021 in Mathematics
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Differential evolution (DE) is a simple and efficient population-based stochastic algorithm for solving global numerical optimization problems. DE largely depends on algorithm parameter values and search strategy. Knowledge on how to tune the best values of these parameters is scarce. This paper aims to present a consistent methodology for tuning optimal parameters. At the heart of the methodology is the use of an artificial neural network (ANN) that learns to draw links between the algorithm performance and parameter values. To do so, first, a data-set is generated and normalized, then the ANN approach is performed, and finally, the best parameter values are extracted. The proposed method is evaluated on a set of 24 test problems from the Black-Box Optimization Benchmarking (BBOB) benchmark. Experimental results show that three distinct cases may arise with the application of this method. For each case, specifications about the procedure to follow are given. Finally, a comparison with four tuning rules is performed in order to verify and validate the proposed method’s performance. This study provides a thorough insight into optimal parameter tuning, which may be of great use for users.

ACS Style

Manu Centeno-Telleria; Ekaitz Zulueta; Unai Fernandez-Gamiz; Daniel Teso-Fz-Betoño; Adrián Teso-Fz-Betoño. Differential Evolution Optimal Parameters Tuning with Artificial Neural Network. Mathematics 2021, 9, 427 .

AMA Style

Manu Centeno-Telleria, Ekaitz Zulueta, Unai Fernandez-Gamiz, Daniel Teso-Fz-Betoño, Adrián Teso-Fz-Betoño. Differential Evolution Optimal Parameters Tuning with Artificial Neural Network. Mathematics. 2021; 9 (4):427.

Chicago/Turabian Style

Manu Centeno-Telleria; Ekaitz Zulueta; Unai Fernandez-Gamiz; Daniel Teso-Fz-Betoño; Adrián Teso-Fz-Betoño. 2021. "Differential Evolution Optimal Parameters Tuning with Artificial Neural Network." Mathematics 9, no. 4: 427.

Journal article
Published: 27 January 2021 in Materials
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One of the materials that is used widely for wind turbine blade manufacturing are fiber-reinforced composites. Although glass fiber reinforcement is the most used in wind turbine blades, the use of carbon fiber allows larger blades to be manufactured due to their better mechanical characteristics. Some turbine manufacturers are using carbon fiber in the most critical parts of the blade design. The larger rotors are exposed to complex loading conditions in service. One of the most relevant structures on a wind turbine blade is the spar cap. It is usually manufactured by means of unidirectional laminates, and one of its major failures is the delamination. The determination of material features that influence delamination initiation and advance by appropriate testing is a fundamental topic for the study of composite delamination. The fracture behavior is studied across coupons of carbon fiber reinforcement epoxy laminates. Fifteen different test conditions have been analyzed. Fracture surfaces for different mode ratios have been explored using optical microscope and scanning electron microscope. Experimental results shown in the paper for critical fracture parameters agree with the theoretically expected values. Therefore, this experimental procedure is suitable for wind turbine blade material characterizing at the initial coupon-scale research level.

ACS Style

Ana Boyano; Jose Lopez-Guede; Leyre Torre-Tojal; Unai Fernandez-Gamiz; Ekaitz Zulueta; Faustino Mujika. Delamination Fracture Behavior of Unidirectional Carbon Reinforced Composites Applied to Wind Turbine Blades. Materials 2021, 14, 593 .

AMA Style

Ana Boyano, Jose Lopez-Guede, Leyre Torre-Tojal, Unai Fernandez-Gamiz, Ekaitz Zulueta, Faustino Mujika. Delamination Fracture Behavior of Unidirectional Carbon Reinforced Composites Applied to Wind Turbine Blades. Materials. 2021; 14 (3):593.

Chicago/Turabian Style

Ana Boyano; Jose Lopez-Guede; Leyre Torre-Tojal; Unai Fernandez-Gamiz; Ekaitz Zulueta; Faustino Mujika. 2021. "Delamination Fracture Behavior of Unidirectional Carbon Reinforced Composites Applied to Wind Turbine Blades." Materials 14, no. 3: 593.

Journal article
Published: 01 January 2021 in Journal of Modern Power Systems and Clean Energy
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ACS Style

Jon Martinez-Rico; Ekaitz Zulueta; IsmaelRuizdeArgando馻; Unai Fernandez-Gamiz; Mikel Armendia. Multi-objective Optimization of Production Scheduling Using Particle Swarm Optimization Algorithm for Hybrid Renewable Power Plants with Battery Energy Storage System. Journal of Modern Power Systems and Clean Energy 2021, 9, 285 -294.

AMA Style

Jon Martinez-Rico, Ekaitz Zulueta, IsmaelRuizdeArgando馻, Unai Fernandez-Gamiz, Mikel Armendia. Multi-objective Optimization of Production Scheduling Using Particle Swarm Optimization Algorithm for Hybrid Renewable Power Plants with Battery Energy Storage System. Journal of Modern Power Systems and Clean Energy. 2021; 9 (2):285-294.

Chicago/Turabian Style

Jon Martinez-Rico; Ekaitz Zulueta; IsmaelRuizdeArgando馻; Unai Fernandez-Gamiz; Mikel Armendia. 2021. "Multi-objective Optimization of Production Scheduling Using Particle Swarm Optimization Algorithm for Hybrid Renewable Power Plants with Battery Energy Storage System." Journal of Modern Power Systems and Clean Energy 9, no. 2: 285-294.

Review
Published: 31 December 2020 in Energies
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Large-scale energy storage systems (ESS) are nowadays growing in popularity due to the increase in the energy production by renewable energy sources, which in general have a random intermittent nature. Currently, several redox flow batteries have been presented as an alternative of the classical ESS; the scalability, design flexibility and long life cycle of the vanadium redox flow battery (VRFB) have made it to stand out. In a VRFB cell, which consists of two electrodes and an ion exchange membrane, the electrolyte flows through the electrodes where the electrochemical reactions take place. Computational Fluid Dynamics (CFD) simulations are a very powerful tool to develop feasible numerical models to enhance the performance and lifetime of VRFBs. This review aims to present and discuss the numerical models developed in this field and, particularly, to analyze different types of flow fields and patterns that can be found in the literature. The numerical studies presented in this review are a helpful tool to evaluate several key parameters important to optimize the energy systems based on redox flow technologies.

ACS Style

Iñigo Aramendia; Unai Fernandez-Gamiz; Adrian Martinez-San-Vicente; Ekaitz Zulueta; Jose Manuel Lopez-Guede. Vanadium Redox Flow Batteries: A Review Oriented to Fluid-Dynamic Optimization. Energies 2020, 14, 176 .

AMA Style

Iñigo Aramendia, Unai Fernandez-Gamiz, Adrian Martinez-San-Vicente, Ekaitz Zulueta, Jose Manuel Lopez-Guede. Vanadium Redox Flow Batteries: A Review Oriented to Fluid-Dynamic Optimization. Energies. 2020; 14 (1):176.

Chicago/Turabian Style

Iñigo Aramendia; Unai Fernandez-Gamiz; Adrian Martinez-San-Vicente; Ekaitz Zulueta; Jose Manuel Lopez-Guede. 2020. "Vanadium Redox Flow Batteries: A Review Oriented to Fluid-Dynamic Optimization." Energies 14, no. 1: 176.

Journal article
Published: 20 December 2020 in Energies
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Microtabs (MTs) are a regularly used flow control device in terms of wind turbine optimization. The present study introduces the application of the novel cell-set model for an MT implementation on a DU91W(2)250 airfoil. The cell-set model is based on the reusability of a mesh to add new geometries on the domain; the matching geometry is located where the user requires, and a set of cells is constructed around the mentioned geometry. Subsequently, wall boundaries are assigned to the generated region. Computational simulations were carried out for fully mesh and cell-set models: MT lengths were set at 1.0%, 1.5% and 2.0% of the airfoil chord length (c) and the MTs were placed at 93% and 95% of c from the leading edge of the airfoil. Resulting data showed that the MT behavior was similar for both models with regard to aerodynamic performance curve representations. A global relative error of 3.784% was obtained for the cell-set model and a maximum relative error of 7.332% was determined. Qualitatively, both models generated significantly similar flow stream velocity wakes on the trailing edge area of the airfoil.

ACS Style

Alejandro Ballesteros-Coll; Unai Fernandez-Gamiz; Iñigo Aramendia; Ekaitz Zulueta; José Antonio Ramos-Hernanz. Cell-Set Modelling for a Microtab Implementation on a DU91W(2)250 Airfoil. Energies 2020, 13, 6723 .

AMA Style

Alejandro Ballesteros-Coll, Unai Fernandez-Gamiz, Iñigo Aramendia, Ekaitz Zulueta, José Antonio Ramos-Hernanz. Cell-Set Modelling for a Microtab Implementation on a DU91W(2)250 Airfoil. Energies. 2020; 13 (24):6723.

Chicago/Turabian Style

Alejandro Ballesteros-Coll; Unai Fernandez-Gamiz; Iñigo Aramendia; Ekaitz Zulueta; José Antonio Ramos-Hernanz. 2020. "Cell-Set Modelling for a Microtab Implementation on a DU91W(2)250 Airfoil." Energies 13, no. 24: 6723.

Journal article
Published: 09 December 2020 in Sensors
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In this work, a semi-submersible piezoelectric energy harvester was used to provide power to a low-cost 4G Arduino shield. Initially, unsteady Reynolds averaged Navier–Stokes (URANS)-based simulations were conducted to investigate the dynamic forces under different conditions. An adaptive differential evolution (JADE) multivariable optimization algorithm was used for the power calculations. After JADE optimization, a communication cycle was designed. The shield works in two modes: communication and power saving. The power-saving mode is active for 285 s and the communication mode for 15 s. This cycle consumes a determinate amount of power, which requires a specific piezoelectric material and, in some situations, an extra power device, such as a battery or supercapacitor. The piezoelectric device is able to work at the maximum power point using a specific Insulated Gate Bipolar Transistor (IGBT) H-bridge controlled with a relay action. For the extra power supply, a bidirectional buck–boost converter was implemented to flow the energy in both directions. This electronic circuit was simulated to compare the extra power supply and the piezoelectric energy harvester behavior. Promising results were obtained in terms of power production and energy storage. We used 0.59, 0.67 and 1.69 W piezoelectric devices to provide the energy for the 4G shield and extra power supply device.

ACS Style

Daniel Teso-Fz-Betoño; Iñigo Aramendia; Jon Martinez-Rico; Unai Fernandez-Gamiz; Ekaitz Zulueta. Piezoelectric Energy Harvesting Controlled with an IGBT H-Bridge and Bidirectional Buck–Boost for Low-Cost 4G Devices. Sensors 2020, 20, 7039 .

AMA Style

Daniel Teso-Fz-Betoño, Iñigo Aramendia, Jon Martinez-Rico, Unai Fernandez-Gamiz, Ekaitz Zulueta. Piezoelectric Energy Harvesting Controlled with an IGBT H-Bridge and Bidirectional Buck–Boost for Low-Cost 4G Devices. Sensors. 2020; 20 (24):7039.

Chicago/Turabian Style

Daniel Teso-Fz-Betoño; Iñigo Aramendia; Jon Martinez-Rico; Unai Fernandez-Gamiz; Ekaitz Zulueta. 2020. "Piezoelectric Energy Harvesting Controlled with an IGBT H-Bridge and Bidirectional Buck–Boost for Low-Cost 4G Devices." Sensors 20, no. 24: 7039.

Journal article
Published: 02 December 2020 in Journal of Marine Science and Engineering
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Passive flow control devices are included in the design of wind turbine blades in order to obtain better performance and reduce loads without consuming any external energy. Vortex Generators are one of the most popular flow control devices, whose main objective is to delay the flow separation and increase the maximum lift coefficient. Computational Fluid Dynamics (CFD) simulations of a Vortex Generator (VG) on a flat plate in negligible streamwise pressure gradient conditions with the fully-resolved mesh model and the cell-set model using Large Eddy Simulation (LES) and Reynolds-Averaged Navier–Stokes (RANS) were carried out, with the objective of evaluating the accuracy of the cell-set model taking the fully-resolved mesh model as benchmark. The implementation of the cell-set model entailed a considerable reduction of the number of cells, which entailed saving simulation time and resources. The coherent structures, vortex path, wall shear stress and size, strength and velocity profiles of the primary vortex have been analyzed. The results show good agreements between the fully-resolved mesh model and the cell-set mode with RANS in all the analyzed parameters. With LES, acceptable results were obtained in terms of coherent structures, vortex path and wall shear stress, but slight differences between models are visible in the size, strength and velocity profiles of the primary vortex. As this is considered the first application of the cell-set model on VGs, further research is proposed, since the implementation of the cell-set model can represent an advantage over the fully-resolved mesh model.

ACS Style

Iosu Ibarra-Udaeta; Koldo Portal-Porras; Alejandro Ballesteros-Coll; Unai Fernandez-Gamiz; Javier Sancho. Accuracy of the Cell-Set Model on a Single Vane-Type Vortex Generator in Negligible Streamwise Pressure Gradient Flow with RANS and LES. Journal of Marine Science and Engineering 2020, 8, 982 .

AMA Style

Iosu Ibarra-Udaeta, Koldo Portal-Porras, Alejandro Ballesteros-Coll, Unai Fernandez-Gamiz, Javier Sancho. Accuracy of the Cell-Set Model on a Single Vane-Type Vortex Generator in Negligible Streamwise Pressure Gradient Flow with RANS and LES. Journal of Marine Science and Engineering. 2020; 8 (12):982.

Chicago/Turabian Style

Iosu Ibarra-Udaeta; Koldo Portal-Porras; Alejandro Ballesteros-Coll; Unai Fernandez-Gamiz; Javier Sancho. 2020. "Accuracy of the Cell-Set Model on a Single Vane-Type Vortex Generator in Negligible Streamwise Pressure Gradient Flow with RANS and LES." Journal of Marine Science and Engineering 8, no. 12: 982.

Conference paper
Published: 29 August 2020 in Advances in Intelligent Systems and Computing
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Autonomous Mobile Robots (AMR) need a positioning function to move into unknown areas. These kinds of vehicles do not use a magnetic tape to guide into warehouses. Therefore, AMR use two different alternative techniques to solve the localization problem. First one is based on absolute positioning, and second one is established on relative localization. The absolute localization uses Simultaneous Localization and Mapping algorithms, in order to obtain a global position. However, the relative localization is based on odometry techniques. With the intention of developing a navigation system for an industrial mobile robot, which is being programmed in a structured text language, a relative localization is done utilizing LiDAR data acquisition. This novel concept analyzes two LiDAR datasets from different periods to calculate the AMR movement, by implementing Point matching and Linear Regression (LR) techniques. To understand the differences between conventional Iterative Closest Point (ICP) and LR a comparison is performed.

ACS Style

Daniel Teso-Fz-Betoño; Ekaitz Zulueta; Ander Sánchez-Chica; Unai Fernandez-Gamiz; Irantzu Uriarte; Jose Manuel Lopez-Guede. A Relative Positioning Development for an Autonomous Mobile Robot with a Linear Regression Technique. Advances in Intelligent Systems and Computing 2020, 627 -635.

AMA Style

Daniel Teso-Fz-Betoño, Ekaitz Zulueta, Ander Sánchez-Chica, Unai Fernandez-Gamiz, Irantzu Uriarte, Jose Manuel Lopez-Guede. A Relative Positioning Development for an Autonomous Mobile Robot with a Linear Regression Technique. Advances in Intelligent Systems and Computing. 2020; ():627-635.

Chicago/Turabian Style

Daniel Teso-Fz-Betoño; Ekaitz Zulueta; Ander Sánchez-Chica; Unai Fernandez-Gamiz; Irantzu Uriarte; Jose Manuel Lopez-Guede. 2020. "A Relative Positioning Development for an Autonomous Mobile Robot with a Linear Regression Technique." Advances in Intelligent Systems and Computing , no. : 627-635.

Journal article
Published: 27 July 2020 in Scientific Reports
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In this article authors propose a temperature based Maximum Power Point Tracking algorithm (MPPT). Authors show that there is an optimal current vs maximum power curve that depends on photovoltaic (PV) module temperature. Therefore, the maximum power point (MPP) can be achieved in very few commutation steps if the control forces the PV module to work in temperature dependent optimal curve. Authors shows how this PV module temperature based MPPT is stable and converges to MPP for each temperature. In order to proof its stability, authors propose a Lyapunov energy function. This Lyapunov energy function has positive values for all values except into MPP given the PV module temperature. This Lyapunov energy function has negative increment along each time step. Hence, the stability of temperature based MPPT can be demonstrated. The proposed MPPT algorithm proposes a current set point. This current set point is obtained with instantaneous PV module power and temperature dependent maximum power vs optimal current curve. Stability is analysed for different temperature levels. Optimal current vs maximum power curve has been modelled by a line. The lines’ coefficients depend on PV module temperature. Proposed Lyapunov energy function is not symmetric about equilibrium or MPP because MPPT algorithm and PV module dynamic have no symmetric behaviour about this equilibrium point.

ACS Style

Josean Ramos-Hernanz; Irantzu Uriarte; Jose Manuel Lopez-Guede; Unai Fernandez-Gamiz; Amaia Mesanza; Ekaitz Zulueta. Temperature based maximum power point tracking for photovoltaic modules. Scientific Reports 2020, 10, 1 -10.

AMA Style

Josean Ramos-Hernanz, Irantzu Uriarte, Jose Manuel Lopez-Guede, Unai Fernandez-Gamiz, Amaia Mesanza, Ekaitz Zulueta. Temperature based maximum power point tracking for photovoltaic modules. Scientific Reports. 2020; 10 (1):1-10.

Chicago/Turabian Style

Josean Ramos-Hernanz; Irantzu Uriarte; Jose Manuel Lopez-Guede; Unai Fernandez-Gamiz; Amaia Mesanza; Ekaitz Zulueta. 2020. "Temperature based maximum power point tracking for photovoltaic modules." Scientific Reports 10, no. 1: 1-10.