36 research outputs found
PIV Experimental Comparison of Vertical Axis Wind Turbine Wake with Theoretical Models
No full textVertical Axis Wind Turbine (VAWT) operation is characterized by complex and unsteady three-dimensional fluid dynamics, which presents considerable challenges. One of the crucial points to understand is the complex interaction between rotor, inflow, and wake systems. If we can demonstrate its effectiveness in the complex flow/inflow conditions, will be of great importance. To investigate the wake/wind aerodynamics validate state-of-the-art VAWT wake models, a high ¬fidelity experimental measurement in the domain of VAWT wakes is needed. Computational fluid dynamics (CFD) models for complex wind interactions are far from being feasible. These models are highly time-devouring and computationally expensive, and their cost prohibits the simulation of complex flow configurations. This is usually overcome through the implementation of simple and computationally inexpensive analytical wake models, where the flow conditions are solved through simple analytic expressions and only over specific points of interest. The work aims to realize and validate a simple and efficient analytical wake model (Abkar, 2019 [2]), (Bastankhah & Porté¬Agel, 2014 [7]) for prediction of the wind velocity profile downwind of a VAWT turbine: The best by comparing the modeling results with a set of particle image velocimetry (PIV) measurements of the wakes of an in-house designed VAWT are used as a high-fidelity reference. The present work evaluates and quantifies the influence of the wake deflection produced by the pitch angles of the blades on the scaled VAWT turbine. It reproduces the main phenomena involved in the flow pattern and identifies the general structure of the resulting wake that occurs: under the influence of pitching the blades on the upstream turbine. The configuration consists of a VAWT aligned in the direction of the incoming flow: With a class of cases for different configurations of the turbine are studied for example ¬ deflection of wake through zero pitch, positive 10 degrees pitch, Negative 10 degrees pitch angles (Mendoza et al, 2019 [32]). The available power distribution over other hypothetical downwind turbines due to the influence of wake deflection by the upstream turbine is studied and reported. These interactions are measured with the help of large ¬scale PIV experiments in OJF, TU Delft. Also, an efficacious force balance system for the VAWT rotor is studied, designed, and fabricated (in-house) to calculate the accurate lift and drag forces on the VAWT structure. The stereo particle image velocimetry results are compared with two theoretical works Jensen wake model, [21] and Gaussian-based wake model Abkar [2] and CFD simulations by Huang et al [18]. The study shows a wake shift towards the windward side (cross-flow width), Negative¬ Y direction. For all the pitch cases, maximum for the positive pitch angle and least for a negative pitch angle. The wake shift in the negative ¬Y direction can be caused by the blade rotation, with the clockwise rotation of the VAWT rotor, and the rear blade turning into the incoming flow of wind. The theoretical models especially the Gaussian-based wake model represent the wake deficit in close agreement to the experimental results but fails to account for wake shift and change in wake structure. The CFD simulations reproduce the 3D wake structures consistent with the experiment results but show an early recovery in the wake. The wake recovery with downwind available power is found higher with a positive pitch angle and least with the negative pitch. A study of in-plane velocity vectors indicates crosswind force introducing crosswind momentum to the flow and as a result would give rise to the CVPs, also according to a study by Rolin F, Porte-Agel [38]. The theoretical models do not account for any of these structural changes in wake and the deflections in them. Furthermore, the suitability of these experimental references are used to verify the CFD simulations and analytical models’ range of the fidelityElectrical Engineering | Sustainable Energy Technolog
Underling data for "On the wake deflection of vertical axis wind turbines by fixed-pitched blades"
No full textThe repository contains the underlining data for "On the wake deflection of vertical axis wind turbines by pitched blades"
This repository consists of experimental (PIV and force measurements) data in the wake of VAWTs with different blade pitch angles. The measured cases include an isolated VAWT with -10, 0, 10 degree pitch, respectively.
Author contribution:
Ming Huang: Conceptualization; Methodology; Validation; Experimental design; Carrying out the experiment; postprocessing
Yugandhar Vijaykumar Patil: Design assistant; Carrying out the experiment; postprocessing
Andrea Sciacchitano: Conceptualization; Experimental design; Methodology; Validation;
Delphine De Tavernier: Conceptualization
Carlos Simao Ferreira: Conceptualization; Methodology; Validation; Experimental design
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Sugarcane Bagasse – A By-Product of Sugar Industry, Its Characterisation and Utilization in the Preparation of High Fiber Biscuits
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Underling data for "On the wake deflection of vertical axis wind turbines by fixed-pitched blades"
No full textThe repository contains the underlining data for "On the wake deflection of vertical axis wind turbines by pitched blades"
This repository consists of experimental (PIV and force measurements) data in the wake of VAWTs with different blade pitch angles. The measured cases include an isolated VAWT with -10, 0, 10 degree pitch, respectively.
Author contribution:
Ming Huang: Conceptualization; Methodology; Validation; Experimental design; Carrying out the experiment; postprocessing
Yugandhar Vijaykumar Patil: Design assistant; Carrying out the experiment; postprocessing
Andrea Sciacchitano: Conceptualization; Experimental design; Methodology; Validation;
Delphine De Tavernier: Conceptualization
Carlos Simao Ferreira: Conceptualization; Methodology; Validation; Experimental design
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Study of magnetofluidic laser scattering under rotating magnetic field
No full textMagnetic field driven self-assembly of magnetic nanoparticles provides wireless programmable approach for tunable magnetofluidic laser scattering. In this work, we study magnetofluidic laser scattering from a commercial aqueous magnetic fluid (EMG 707) under an external rotating magnetic field. A set-up is developed to generate rotating magnetic field for the purpose. Self-assembled magnetic nanoparticle structures in the form of chains and bundles are formed along the magnetic field. This creates a linear streak formation in the forward laser scattering. Rotating magnetic field produces rotating linear streak. We report our initial results of rotating linear streaks at 3 rpm, 6 rpm and 10 rpm and our analysis of the patterns. The studies are useful for developing magnetic fluid based optical devices.Published versio
Comparative Experimental Study on Torsional Behavior of RC Beam Using CFRP and GFRP Fabric Wrapping
No full textAbstractFiber reinforced polymer (FRP) as an external reinforcement is used extensively to enhance the strength requirement related to flexure and shear in structural systems. But the strengthening of members subjected to torsion is yet to be explored as Torsion failure is a brittle form of failure. In present experimental study deals with the torsional strengthening of Reinforced Concrete beams using epoxy bonded Fiber- Reinforced Polymer (FRP) fabric. Total Thirty nine rectangular beams of size 150mm × 300mm and 1200 in length are casted. Out of which, three beams are control beam and remaining thirty six beams are classified into two groups. One with CFRP fabric wrapping and another with GFRP fabric wrapping. With various wrapping patterns. The applied CFRP and GFRP configurations are U-jacketed, vertical strips with spacing, and edge strips along with vertical strips along its entire length. Torsional capacity of beams of two groups is compared with control specimen with respect to torsional moment, angle of twist and ductility factor and it was observed that CFRP fabric bonded beam shows more torsional strength than the GFRP bonded beam
Experimental study of the wake interaction between two vertical axis wind turbines
No full textWakes and wake interactions in wind turbine arrays diminish energy output and raise the risk of structural fatigue; hence, comprehending the features of rotor–wake interactions is of practical relevance. Previous studies suggest that vertical axis wind turbines (VAWTs) can facilitate a quicker wake recovery. This study experimentally investigates the rotor–wake and wake–wake interaction of VAWTs; different pitch angles of the blades of the upwind VAWT are considered to assess the interactions for different wake deflections. With stereoscopic particle image velocimetry, the wake interactions of two VAWTs are analysed in nine distinct wake deflection and rotor location configurations. The time-average velocity fields at several planes upwind and downwind from the rotors are measured. Additionally, time-average loads on the VAWTs are measured via force balances. The results validate the rapid wake recovery and the efficacy of wake deflection, which increases the available power in the second rotor.Wind EnergyAerodynamic
The design and synthesis of novel N-heterocyclic compounds, and their evaluation of anti-cancer and anti-viral activity
No full text2010 - 2011The thesis entitled “The design and synthesis of novel N-heterocyclic compounds, and their evaluation of anti-cancer and anti-viral activity" is divided into three chapters.
The title of the thesis clearly reflects the importance of nitrogen heterocycles compounds: in fact they are extremely pivotal structural motifs responsible for eliciting various biological activities in natural products and synthetic medicines. This has attracted the medicinal chemists towards the synthesis of various compounds having nitrogen heterocycles as useful medicines to treat various diseases. It is also evident by a large number of marketed pharmaceutical products possess nitrogen heterocycles. In each chapter different heterocycle moieties belonging to β-carboline, indoles and isoindolinones nucleus respectively are presented.
In the first chapter we presented β-carboline derivatives and their anticancer activity on different cell lines. Our lead compound was harmine, which is the most representative β-carboline alkaloid endowed with antitumor properties showing high cytotoxicity both in vitro against different human tumor cell lines and in vivo. It also exhibited remarkable DNA intercalation capacity and significant Topo I inhibition activity. We designed and synthesized novel β-carbolines derivatives with the aim to evaluate their antiproliferative properties, to acquire more information about the structural requirements for the possible improvement of the cytotoxic potential and to elucidate SARs between substituent properties and antitumor activities. Most of the compounds were evaluated for Topo I inhibitory activity and compaired to harmine. Almost all compounds demonstrated interesting cytotoxic activities in particular against prostate cancer cells PC-3 with IC50 in low micromolar range. Compound X was found to be the most potent one with IC50 value of 8 µM.
In the second chapter we reported the design and synthesis of new arbidol derivatives as antiviral agents: arbidol is an indole compound launched in the Russian Federation for the prophylaxis and treatment of influenza A and B and other acute respiratory viral infections, but due to its relatively high CC50 value, a clinical application is forbidden. So in order to reduce its toxicity and improve its antiviral properties, we carried out some structural modifications at position 2, 4, 5 and 6 on indole nucleus and we evaluated their effect on in vitro, anti- influenza virus (HA), hepatitis C virus (HCV) and chikungunya virus (CHIKV) activities. Viral infections are in fact the most common illnesses experienced by people of all ages and they are also one of the major causes of morbidity and mortality in elderly people and young children throughout the world. Currently, treatments are limited and the increasing prevalence of drug-resistant pathogens highlighted the need for new anti-viral drugs with novel mechanisms of action. Biological evaluation led us to discovery of a new potent influenza virus replication inhibitor, identified in compound 15. Particularly it showed activity against all the tested viruses, both A and B type; moreover it seemed to lead to a better inhibition of some viruses in comparison to Arbidol. This compound was also found to be a promising lead compound for the design of new HCV virus replication inhibitors. Actually, biological study are in course to better study mechanism underwent the action of compound 15, which could act non only as virus replication inhibitor but also as fusion inhibitor. Then a focused analysis on the interaction of this compound with the HA protein will be carried out.
The third chapter is divided into two sections.
Section A provided a brief introduction about aldol addition to 1,3-dicarbonyl compounds and described a simple and effective multicomponent regioselective one pot aldol addition/protection reaction of β-ketoesters to a series of aldehydes in the presence of Me3SiCl and i-Pr2EtN. The analysis of the scope and application of reaction revealed a dramatic dependence of the reactivity on the used substrates.
Section B described a simple and general access to a series of new phthalimidines derivatives, (mentioned in Section A) in the presence of tertiary amines under very mild conditions exploiting the aldol addition of readily enolizable 1,3 dicarbonyl compounds to 2-cyanobenzaldehyde. Recently, it has been recognized that 3-substituted isoindolinones possess a variety of biological activity, consequently, considerable effort has been devoted to the synthesis of this nitrogen heterocycle, which also act as useful synthetic building blocks and intermediates in organic synthesis.
The obtained 3-substituted isoindolinones were preliminary tested on two different virus strains (HCV and CHIKV virus) to evaluate potential activity on the virus replication, but unfortunately it was found that all compounds were not active. However further studies are desirable focusing on activities like hypnothic, anti-schizophrenia etc, for which isoindolinone moiety also shows important applications. [edited by author]X n.s
