Artificial Vortex Research Articles

Computational analysis of the inflow air slot size influence on solar vortex generator peformance

Nowadays, attention is directed towards the possibilities of harnessing the potential of tornado by creating an artificial convective vortices for green electricity generation. In view of this research trending, a novel new solar vortex power generator, designed, fabricated and experimented at University Technology PETRONAS, Malaysia. In this paper, ANSYS - FLUENT 15 software was used to simulate the influence of inflow slot size on the vortex updraft velocity. Two cases hav been investigated. Case 1 with new dimension of 0.1 m width and guide vane height of 0.6 m. Whereas, case 2 with slot dimension of 0.3 m height and 0.15 m width. From the attained results, it could be deduced that the slot size is an important parameter which impacts on the vortex strength. The vortex exit velocity increased by 50% a nd by 2.6% for the case 1 and case 2, respectively. This indicates that the slot height is highly influencing the vortex strength. Thus far, the indexes from the numerical simulation can be used in re-designing of the inflow slot size for optimal performance.

Review and comparative analysis of vortex generation systems for sustainable electric power production

This study presents a review and comparison on the power generation by artificial vortex approach. The basic principles of the artificial vortex theory are presented to comprehend the topic. The main characteristics of the components, working principles and features of the existing Vortex Generator Systems for the production of electricity have been discussed and compared. The literature demonstrates that there are two ways to establish the vortex updraft flow: (i) by constructing a special design of the updraft tower to yield a vertical pressure gradient along the axis of a vortex. These types of system have a high investment cost due to the tall tower, or (ii) by using an external heat source to create large temperature rise in ambient air and enhance the buoyancy forces. This integration between the vortex generation system and the wasted heat source is restricted operation in the industrial areas. Therefore, enhancement and development of the way to use a simple construction design based on the solar energy as a heat source support the technology of electricity production by artificial vortex generation. A solar based vortex power generator could be a potential technology for electric power generation, especially in the desert and rural areas.

Initializing the WRF Model with Tropical Cyclone Real-Time Reports Using the Ensemble Kalman Filter Algorithm

This study presents an approach to assimilate tropical cyclone (TC) real-time reports and the University of Wisconsin-Cooperative Institute for Meteorological Satellite Studies (CIMSS) Atmospheric Motion Vectors (AMV) data into the Weather Research and Forecasting (WRF) model for TC forecast applications. Unlike current methods in which TC real-time reports are used to either generate a bogus vortex or spin up a model initial vortex, the proposed approach ingests the TC real-time reports through blending a dynamically consistent synthetic vortex structure with the CIMSS-AMV data. The blended dataset is then assimilated into the WRF initial condition, using the local ensemble transform Kalman filter (LETKF) algorithm. Retrospective experiments for a number of TC cases in the northwestern Pacific basin during 2013–2014 demonstrate that this approach could effectively increase both the TC circulation and enhance the large-scale environment that the TCs are embedded in. Further evaluation of track and intensity forecast errors shows that track forecasts benefit more from improvement in the large-scale flow at 4–5-day lead times, whereas the intensity improvement is minimal. While the difference between the track and intensity improvement could be due to a specific model configuration, this result appears to be consistent with the recent reports of insignificant impacts of inner core data assimilation in operational TC models at the long range of 4–5 days. The new approach will be most beneficial for future regional TC models that are directly initialized from very high-resolution global models whose storm initial locations are sufficiently accurate at the initial analysis that there is no need to carry out any artificial vortex removal or filtering steps.

Dynamic Control of the Vortex Pinning Potential in a Superconductor Using Current Injection through Nanoscale Patterns.

Control over the vortex potential at the nanoscale in a superconductor is a subject of great interest for both fundamental and technological reasons. Many methods for achieving artificial pinning centers have been demonstrated, for example, with magnetic nanostructures or engineered imperfections, yielding many intriguing effects. However, these pinning mechanisms do not offer dynamic control over the strength of the patterned vortex potential because they involve static nanostructures created in or near the superconductor. Dynamic control has been achieved with scanning probe methods on the single vortex level but these are difficult so scale up. Here, we show that by applying controllable nanopatterned current injection, the superconductor can be locally driven out of equilibrium, creating an artificial vortex potential that can be tuned by the magnitude of the injected current, yielding a unique vortex channeling effect.

Study of the vortex principle for improving the efficiency of an exhaust ventilation system

In both industrial and civil buildings, local exhaust ventilation systems are widely used in pollutant control. The efficiency of such systems has an important influence on indoor air quality and energy consumption. A tornado is a type of rotating vortex with strong suction force that can lift heavy weights into the atmosphere. This article presents a novel type of artificial vortex exhaust device (AVED) using the principle of tornado-like vortex to improve the efficiency of local exhaust system. The formation of a tornado-like vortex requires a circular updraft fed by air possessing angular momentum with respect to the updraft center axis. To understand the flow characteristics of AVED, the velocity distribution and pressure distribution are investigated by varying the following parameters via experimental methods: radius ratio, lifting ratio, control distances, velocity of the jets and flow rate of exhaust hood. The experimental results indicate that increasing the velocity of the jets is beneficial to forming vortex, and the appropriate range to form an optimal vortex of the radius ratio is 1 to 2, and that of the lifting ratio is 0.127 to 0.256. Compared to the ordinary canopy exhaust hood, AVED has at least twice the control distance while only requiring less than half the flow rate of the exhaust hood.

Size does matter: The use of fish motion for improving human swimming simulations

In this study we evaluated the length and volume inconsistencies that occur when applying simple motion functions onto surface models of swimming fish and human, respectively. The larger the size (diameter and length) of the body, the larger are these inconsistencies. To eliminate these errors, different surface correction algorithms are introduced. Additional terms are implemented to overcome structural insufficiencies through over-stretching and overlapping in sensible body parts. For human undulatory swimming these models combine the motion of rigid extremities with the smooth surface bending at joints. The advantages of this hybrid model can be crucial for Computational Fluid Dynamics, where deviation from natural behaviour results in unrealistic surface pressures and artificial vortex structures. The structural improvements are also promising for computational graphic programming, where skin-like stretching surfaces mediate a natural impression.

Optimization of self‐learning in Computer Engineering courses: An intelligent software system supported by Artificial Neural Network and Vortex Optimization Algorithm

ABSTRACTSelf‐learning process is an important factor that enables learners to improve their own educational experiences when they are away of face‐to‐face interactions with the teacher. A well‐designed self‐learning activity process supports both learners and teachers to achieve educational objectives rapidly. Because of this, there has always been a remarkable trend on developing alternative self‐learning approaches. In this context, this study is based on two essential objectives. Firstly, it aims to introduce an intelligent software system, which optimizes and improves computer engineering students’ self‐learning processes. Secondly, it aims to improve computer engineering students’ self‐learning during the courses. As general, the software system introduced here evaluates students’ intelligence levels according to the Theory of Multiple Intelligences and supports their learning via accurately chosen materials provided over the software interface. The evaluation mechanism of the system is based on a hybrid Artificial Intelligence approach formed by an Artificial Neural Network, and an optimization algorithm called as Vortex Optimization Algorithm (VOA). The system is usable for especially technical courses taught at computer engineering departments of universities and makes it easier to teach abstract subjects. For having idea about success of the system, it has been tested with students and positive results on optimizing and improving self‐learning have been obtained. Additionally, also a technical evaluation has been done previously, in order to see if the VOA is a good choice to be used in the system. It can be said that the whole obtained results encourage the authors to continue to future works. © 2017 Wiley Periodicals, Inc. Comput Appl Eng Educ 25:142–156, 2017; View this article online atwileyonlinelibrary.com/journal/cae; DOI10.1002/cae.21787

CFD modeling of artificial vortex air generator for green electric power

This paper presents and discusses a Computational Fluid Dynamics (CFD) simulation of artificial vortex air generator as part of the preliminary of Solar Vortex Power Generator for an electrical power generation. A vortex air generator system was built, consisting of concentric cylinders. The inner cylinder was fitted with stationary air guide vanes and covered at the top by a transparent plate to capture the solar radiation and create swirling updraft flow which is able to rotate wind turbine and produces power. The influence of inlet air velocity and temperature on the swirling strength and mass flow generated has been evaluated by validated CFD simulation. ANSYS Fluent software was adopted to solve the 3-D, steady state of Navier-Stokes and energy equations in cylindrical coordinate system integrated with discrete ordinates (DO) radiation model. For the preliminary vortex generator design, the CFD results were validated first with previous experimental measurements. Then the variable operation parameters were carried out on the proposed model. The simulation result demonstrated that inflow velocity is a key parameter for enhancing the system performance. By increasing the inflow velocity from 0.4 m/s to 0.6 m/s and inflow temperature 323°k the enhancement rate of the mass air flow generated reached to 26 compared with 7 when increase the inflow temperature to 328°k and inflow velocity 0.4 m/s. © The authors, published by EDP Sciences, 2017.

Influence of the Self-Consistent Regional Ensemble Background Error Covariance on Hurricane Inner-Core Data Assimilation with the GSI-Based Hybrid System for HWRF

Abstract An initial vortex spindown, or strong adjustment to the structure and intensity of a hurricane’s initial vortex, presents a significant problem in hurricane forecasting, as with the NCEP Hurricane Weather Research and Forecasting Model (HWRF), because it can cause significantly degraded intensity forecasts. In this study, the influence of the self-consistent regional ensemble background error covariance on assimilating hurricane inner-core tail Doppler radar (TDR) observations in HWRF is examined with the NCEP gridpoint statistical interpolation (GSI)-based ensemble–three-dimensional variational (3DVAR) hybrid data assimilation system. It is found that the resolution of the background error covariance term, coming from the ensemble forecasts, has notable influence on the assimilation of hurricane inner-core observations and subsequent forecasting results. Specifically, the use of ensemble forecasting at high-resolution native grids results in significant reduction of the vortex spindown problem and thus leads to improved hurricane intensity forecasting. Further diagnoses are conducted to examine the spindown problem with a gradient wind balance. It is found that artificial vortex initialization, performed before data assimilation, can cause strong supergradient winds or imbalance in the vortex inner-core region. Assimilation of hurricane inner-core TDR data can significantly mitigate this imbalance by reducing the supergradient effects. Compared with the use of a global ensemble background error term, application of the self-consistent regional ensemble background covariance to inner-core data assimilation leads to better representation of the mesoscale hurricane inner-core structures. It can also result in more realistic vortex structures in data assimilation even when the observational data are unevenly distributed.

Sistema de Generación Energía Sumergible Basado en un Vórtice Gravitacional con Sifón para Comunidades Aisladas

En este trabajo se presenta un sistema de generación de energía eléctrica basado en un vórtice gravitacional con sifón para comunidades aisladas, manufacturado en la provincia de Loja Ecuador. El sistema es sumergible funciona como una central de paso y por su diseño se lo puede instalar directamente en canales de riego, ríos, etc. sin obras civiles importantes. La unidad de generación denominada UTG (Underwater Turbine Generator) está conformada por una turbina Kaplan, un generador sumergible síncrono multi-polo con imanes permanentes, un rectificador, un inversor, un vórtice gravitacional y un sifón de evacuación para ganar energía potencial. Además, incluye un control integrado que permite realizar mediciones de los parámetros eléctricos del sistema. De acuerdo con los resultados de la medición de campo, el prototipo UTG basado en un vórtice gravitacional puede ofrecer de forma estable la energía eléctrica a las cargas conectadas, con un factor de planta del 60%.

A review of convective and artificial vortices for power generation

Thermal energy transfer in the atmosphere occurs from a high temperature zone to a low one by means of convective vortices where mechanical energy is produced. There are two ways of driving vertical flow in the core of a vortex: (1) by the direct action of buoyancy acting on hot air and (2) by producing a vertical pressure gradient along the axis of a vortex because of core development involving the lateral spread of the vortex with height. In particular, it indicates that the intensity of convective vortices depends on the depth of the convective layer via thermodynamic efficiency, the enthalpy perturbation across them, and the existence of sources of vorticity. The atmospheric vortex engine (AVE) is a device for producing an artificial vortex. The operation of AVE is based on the fact that the atmosphere is heated from the bottom and cooled at the top. By artificial vortex generation, it is aimed to eliminate the physical solar updraft tower and reduce the capital cost of solar chimney power plants. This paper reviews natural convective vortices and vortex creation via physical principles of vortex generation. Vortex analysis and modelling are presented. Furthermore, a new model of a solar vortex engine (SVE) is proposed and discussed. An idea on utilizing the solar energy as the heat source for establishing the vortex and operating the SVE model is adopted. The SVE model is feasible and promising for electrical power generation.

Proximity Driven Commensurate Pinning in YBa2Cu3O7 through All-Oxide Magnetic Nanostructures.

The design of artificial vortex pinning landscapes is a major goal toward large scale applications of cuprate superconductors. Although disordered nanometric inclusions have shown to modify their vortex phase diagram and to produce enhancements of the critical current ( MacManus-Driscoll , J. L. ; Foltyn , S. R. ; Jia , Q. X. ; Wang , H. ; Serquis , A. ; Civale , L. ; Maiorov , B. ; Hawley , M. E. ; Maley , M. P. ; Peterson , D. E. Nat. Mater. 2004 , 3 , 439 - 443 and Yamada , Y. ; Takahashi , K. ; Kobayashi , H. ; Konishi , M. ; Watanabe , T. ; Ibi , A. ; Muroga , T. ; Miyata , S. ; Kato , T. ; Hirayama , T. ; Shiohara , Y. Appl. Phys. Lett. 2005 , 87 , 1 - 3 ), the effect of ordered oxide nanostructures remains essentially unexplored. This is due to the very small nanostructure size imposed by the short coherence length, and to the technological difficulties in the nanofabrication process. Yet, the novel phenomena occurring at oxide interfaces open a wide spectrum of technological opportunities to interplay with the superconductivity in cuprates. Here, we show that the unusual long-range suppression of the superconductivity occurring at the interface between manganites and cuprates affects vortex nucleation and provides a novel vortex pinning mechanism. In particular, we show evidence of commensurate pinning in YBCO films with ordered arrays of LCMO ferromagnetic nanodots. Vortex pinning results from the proximity induced reduction of the condensation energy at the vicinity of the magnetic nanodots, and yields an enhanced friction between the nanodot array and the moving vortex lattice in the liquid phase. This result shows that all-oxide ordered nanostructures constitute a powerful, new route for the artificial manipulation of vortex matter in cuprates.

Doped colloidal artificial spin ice

We examine square and kagome artificial spin ice for colloids confined in arrays of double-well traps. Unlike magnetic artificial spin ices, colloidal and vortex artificial spin ice realizations allow creation of doping sites through double occupation of individual traps. We find that doping square and kagome ice geometries produces opposite effects. For square ice, doping creates local excitations in the ground state configuration that produce a local melting effect as the temperature is raised. In contrast, the kagome ice ground state can absorb the doping charge without generating non-ground-state excitations, while at elevated temperatures the hopping of individual colloids is suppressed near the doping sites. These results indicate that in the square ice, doping adds degeneracy to the ordered ground state and creates local weak spots, while in the kagome ice, which has a highly degenerate ground state, doping locally decreases the degeneracy and creates local hard regions.

Optimal Excitation of Asymmetric Perturbations on an Axisymmetric Barotropic Vortex: A Linear Singular-Value Analysis

Abstract Singular vectors on a barotropic circular vortex consisting of three regions of piecewise-constant vorticity are investigated under the L2 norm to reveal the shape and growth rate of possible perturbations that may contribute to the formation of the hierarchal structure seen in natural and artificial vortices. Here, the analytical form of the singular values and the forward and backward singular vectors are derived for comparison with the corresponding eigenvalues and vectors. The results indicate no notable difference between the growing eigenvector and the singular vectors for Michalke and Timme’s profile, which is characterized by a ring of high vorticity. In contrast, for Syōno’s profile, which incorporates a negative vorticity region between a solidly rotating core and potentially rotating surroundings, the pattern of the forward singular vector giving the maximum growth in a specified time interval differs crucially from that of the growing eigenvector: whereas the radial peak of the streamfunction exists solely at the maximum-wind radius of the basic vortex in the growing eigenvector, it shifts outward in the growing forward singular vector. This implies the injection of considerable energy into the outer part of the basic vortex, rather than in the inner ring of the highest wind, facilitating the formation of hierarchal structure concentrated around the core region of the vortex.

Experimental Setup for the Analysis of Vortices

This paper presents a specific experimental setup in which artificial vortices are successfully created and maintained under controlled conditions. The developed vortex simulation chamber is demonstrated to be crucial to the study of vortices and to improve the understanding of vortex nature and behaviour. Furthermore, the general simulation chamber characteristics, constructional details and working principle are elaborated in detail. Preliminary experimental results are also discussed. Specifically, the influence of the water vapour content on the pressure potential and the vortex stability has been analysed. The specific friction work in the vortex system has also been analysed ; the novel specific vortex efficiency factor has been introduced. The gained research results and conclusions are important to understand the complex nature of vortex systems, which can be useful for both meteorological purposes and energy concepts research, where convective vortices are assumed to be used as heat engines.

Strong vortex core pinning and Barkhausen-free magnetization response in thin Permalloy disks induced by implantation of 1 × 104 Ga+ ions

Artificial vortex core pinning sites are induced in thin Permalloy disks by point exposure to as few as 10 000 ions from a focused Ga+ beam. These pinning sites yield a first-order change in the magnetization response of the disk. A single site can keep the vortex core pinned over an applied field range comparable to the vortex annihilation field of the unaltered disk. Several widely separated sites can work together to keep the core pinned in one place, while the Barkhausen effect is eliminated from the magnetization curve over a range approaching the saturation moment of the disk.

Artificial vortex pinning arrays in superconducting films deposited on highly ordered anodic alumina templates

A simple procedure is described for creating periodic vortex pinning centers in thin superconducting NbN films. We report on three different strategies which involve the use of highly ordered alumina templates. In this approach, NbN thin films are deposited either on the porous face of the template made of a triangular array of nanoholes or on the triangular array of bumps formed by the barrier layer or even on the top of perpendicularly oriented ferromagnetic nanowire arrays obtained by electrochemical deposition, thus forming superconductor–ferromagnet hybrids. In all cases, the ordered template allows NbN films to form a periodic pinning array during its growth. The interpore (or inter-bump) distance ranged between 50 and 100 nm and adjustable pore (or wire) diameter was varied between 30 and 60 nm. Numerous matching effects have been observed up to 2.5 T and are maintained at low temperature. These fields are considerably higher than those typical for periodic pinning arrays made by lithographic techniques, which reflects the benefits of nanostructuring superconductors by using self-organized growth to enhance vortex pinning in a large field and temperature range.

Acoustic metric of the compressible draining bathtub

The draining bathtub flow, a cornerstone in the theory of acoustic black holes, is here extended to the case of exact solutions for compressible nonviscous flows characterized by a polytropic equation of state. Investigating the analytical configurations obtained for selected values of the polytropic index, it is found that each of them becomes nonphysical at the so called limiting circle. By studying the null geodesics structure of the corresponding acoustic line elements, it is shown that such a geometrical locus coincides with the acoustic event horizon. This region is characterized also by an infinite value of space-time curvature, so the acoustic analogy breaks down there. Possible applications for artificial and natural vortices are finally discussed.

Technical utilisation of convective vortices for carbon-free electricity production: A review

The instability and unpredictability of future global energy markets necessitate the development of new alternative technical solutions to meet our continuously increasing energy demands. This rapid development has permanent consequences for the environment. This paper analyses several technical solutions and theoretical ideas concerning energy utilisation, i.e. for carbon-free electricity production. The ideas are discussed from theoretical and experimental perspectives. This review focuses on methods of production of an artificial vortex column in the surrounding atmosphere. Namely, convective vortices can be used as heat engines to convert available solar energy into mechanical work. Some of the proposed technical solutions deal with the ability to capture the mechanical energy and produce electricity. The discussion focuses on theoretical models and experimental results. The main aim of this study was to identify the state of the art. The conclusions presented herein may form a basis for further development of this alternative carbon-free concept of energy utilisation.

Numerical simulation of compressible plane jets

Two- and three-dimensional spatial direct numerical simulations of a compressible plane jet exhausting into a parallel stream are described. These simulations reveal the inadequacy of a two-dimensional model in capturing the totality of the flow physics. In two dimensions, instabilities evolve into highly organized large-scale mixing events; two-dimensional time-averaged turbulence quantities also suffer from artificial vortex organization. Mean normal velocity profiles show a significant reduction in entrainment with increased compressibility, while the effect is much less pronounced in three dimensions. While streamwise and spanwise turbulence intensities exhibit no change with increased compressibility, normal intensity and shear stress are significantly reduced.