Nonlinear evolution of harmonically forced perturbations on a wingtip vortex

Wingtip vortices are created by flying airplanes due to lift generation. The vortex interaction with the trailing aircraft has sparked researchers’ interest to develop an efficient technique to destroy these vortices. Different models have been used to describe the vortex dynamics and they all show that, under real flight conditions, the most unstable modes produce a very weak amplification. Another linear instability mechanism that can produce high energy gains in short times is due to the non-normality of the system. Recently, it has been shown that these non-normal perturbations also produce this energy growth when they are excited with harmonic forcing functions. In this study, we analyze numerically the nonlinear evolution of a spatially, pointwise and temporally forced perturbation, generated by a synthetic jet at a given radial distance from the vortex core. This type of perturbation is able to produce high energy gains in the perturbed base flow (10^3), and is also a suitable candidate for use in engineering applications. The flow field is solved for using fully nonlinear three-dimensional direct numerical simulation with a spectral multidomain penalty method model. Our novel results show that the nonlinear effects are able to produce locally small bursts of instability that reduce the intensity of the primary vortex.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Wingtip vortex in a NACA0012 airfoil and its active control

Contribución mediante sesión pósterWe conduct experiments in a towing-tank to analyse the flow patterns of wingtip vortices in a NACA 0012 airfoil. In this experimental research, we provide PIV measurements and flow visualisations. Without active control, several parameters are given experimentally as function of the Reynolds number, so we compare these data with the theoretical models of Batchelor, and Moore and Saffman together with DNS. Secondly, we analyse the effect of a continuous injection in the spanwise direction. The continuous jet has a strong influence on the wing-tip vortex formation. We explore this effect at low chord based Reynolds number ranging from 7000 up to 20000. We change the aspect ratio of the injection, R, defined as the ratio of the velocities between the jet (Uj) and free-stream (U). For R=1, we find that the jet strongly affects the wingtip vortex formation with a sudden decrement of the axial vorticity and the azimuthal velocity. This technique is a challenge and a promising tool to reduce the intensity of the vortex core.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effect of the axial jet on the optimal response in Batchelor vortex

En este póster se estudia la respuesta óptima del torbellino de Batchelor para distintos números de onda. Se demuestra que incluso teniendo la velocidad axial, un torbellino es capaz de tener grandes amplificaciones de energía.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

On the effect of low blowing ratio continuous jets on wingtip vortex characteristics

Vortices are an unavoidable effect of flight, which appear behind the wing with a bounded length. The strength of these vortices, which are extremely stable, is due to the lift force [1]. That is the reason why this phenomenon is especially relevant during take-off and landing operations. In these situations, when aircraft are departing from or arriving to the airport runways, the following aircraft might feel two counter-rotating vortices which remain long time under normal environmental conditions. Unfortunately, this huge rotation of airflow patterns always destabilizes the following aircraft. Consequently, trailing vortices have a mighty influence on the air traffic control of airport runways, and they have justified the research interest in this topic since the 1960's [2]. However, aeronautical engineers are still searching for different technological strategies to breakdown these wingtip vortices.Short-Term Postdoctoral Stay of Talent Attraction Plan of Andalucía TECH ICE. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Mejora de la productividad de las líneas de producción de estufas industriales, estufas semi-industriales freidores y mesas de trabajo de la empresa metalmecánica tecniaceros

Ingeniería Industrialo develop an integral proposal that looks for alternatives to improve the productivity of the Lines of Production of Industrial Heaters, Freidores and desks of the Company Tecniaceros. The investigation presented in the following study is based on an analytical method because which one breaks of an everything it would be the company Metalmecánica Tecniacero and it decomposes in small parts (processes, products, materials, machineries, labor), for the purpose of identifying of a better way the causes that are causing the problems that appear in her. Also, it is based on a bibliographical investigation, which provides the theoretical bases for the study and later solution of the above mentioned problems and in the direct observation for the compilation of the information. As result of the work obtained a proposal in which a uniformity to be achieved both in the processes and in the products, a minimization of the garbage of raw material generated in the production processes of way in which the efficiency is improved in the use of these and an increase in the capacity of the process on having eliminated the effects of the neck of existing bottle in the company, what is reflected in the decrease of late deliveriesDesarrollar una propuesta integral que busque alternativas para mejorar la productividad de las Líneas de Producción de Estufas Industriales, Freidores y mesas de trabajo de la Empresa Tecniaceros. La investigación presentada en el siguiente estudio se basa en un método analítico debido a que se parte de un todo el cual sería la empresa Metalmecánica Tecniacero y se descompone en pequeñas partes (procesos, productos, materiales, maquinarias, mano de obra), con la finalidad de identificar de una mejor manera las causas que están originando los problemas que se presentan en ella. Además, se fundamenta en una investigación bibliográfica, que proporciona las bases teóricas para el estudio y posterior solución de dichos problemas y en la observación directa para la recolección de la información. Como resultado del trabajo se obtuvo una propuesta en la que se lograr una uniformidad tanto en los procesos como en lo productos, una minimización de los desechos de materia prima generados en los procesos de fabricación de manera en que se mejora la eficiencia en el uso de estas y un aumento en la capacidad del proceso al eliminar los efectos del cuello de botella existente en la empresa, lo que se refleja en la disminución de entregas tardía

Ribonucleotides and manganese ions improve non-homologous end joining by human Polμ

Human DNA polymerase mu (Polμ), a family X member involved in DNA repair, has both template-directed and terminal transferase (template-independent) activities. In addition to their ability to incorporate untemplated nucleotides, another similarity between Polµ and terminal deoxynucleotidyl transferase (TdT) is their promiscuity in using ribonucleotides (NTPs), whose physiological significance is presently unknown. As shown here, Polµ can use NTPs instead of deoxynucleotides (dNTPs) during non-homologous end joining (NHEJ) of non-complementary ends, a Polµ-specific task. Moreover, a physiological concentration of Mn 2+ ions did benefit Polµ-mediated NHEJ by improving the efficiency and accuracy of nucleotide insertion. Analysis of different mutations in the ‘steric gate’ of the active site indicated that Polµ is taking advantage of an open active site, valid for selecting alternative activating metal ions and nucleotides as substrates. This versatility would allow ad hoc selection of the most appropriate nucleotide/metal ion combination for individual NHEJ events to gain efficiency without a cost in terms of fidelity, thus widening the spectrum of available solutions to position a discontinuous template strand in proper register for connection

Celos y emociones : factores de la relación de pareja en la reacción ante la infidelidad

Esta investigación está orientada a conocer las diferencias entre hombres y mujeres en las situaciones desencadenantes de celos y cómo estas reacciones son afectadas por ciertas características de las relaciones de pareja. 372 personas (250 mujeres y 122 hombres) que han participado en esta investigación responden ante una hipotética infidelidad de su pareja (infidelidad emocional e infidelidad sexual) con un supuesto rival y a un cuestionario sobre ciertos aspectos de su relación de pareja. Los resultados revelan que las mujeres experimentan una mayor intensidad emocional que los hombres cuando piensan sobre la infidelidad de su pareja, ya sea emocional o sexual. No hay diferencias importantes entre hombres y mujeres en cuanto al tipo de infidelidad que más les molesta: la infidelidad emocional. Además se ha analizado la influencia del tipo de relación de pareja que mantienen los participantes en la experiencia emocional provocada por la infidelidad.This present study explores the differences between women's and men's responses to (hypothetical) infidelity, and how these responses are influenced by the characteristics of the couple's relationship. 372 subjects completed questionnaires (a) itemising their jealous reaction to a partner's hypothetical infidelity (emotional or sexual); and (b) the state of their relationship. A survey of 250 women and 122 men revealed that the women reported higher intensity of emotional distress than the men. in regard to both emotional and sexual infidelity. There were no significant differences between men and women in their reports of which infidelity troubled them more: both genders are troubled more by emotional infidelity. We also report the influence that the type of relationship has on the emotions provoked by the infidelity

PIV measurements of the effect of pulsed blowing jet on a NACA0012 wing model

Wingtip vortices are present in taking off, and landing operations and their presence in airport runways must be reduced. To that end, several strategies have been considered in the last decades, being the active control one possible technical solution. To compute the effectiveness of active control that corresponds to pulsed low-blowing-ratio transverse jet for the reduction of the wingtip vortex strength, we carry out 2D-PIV measurements in a towing tank for chord-based Reynolds numbers 15000 and 20000. We consider two cases: (i) no active control Rjet=0 and (ii) pulsating radial jet of blowing-ratio Rjet smaller than 1.7 (or momentum coefficient lower than 0.12) and different Strouhal numbers ranging from 0.27 to 0.94. Our observations show that the best reduction of wingtip vortex strength takes place at the lowest Strouhal number tested. We use the maximum azimuthal velocity and vorticity together with the circulation to quantify this decrease in the vortex strength. Besides, we define the spatial evolution of a disturbance parameter which allow us to detect again the optimal frequency that leads to vortex destruction.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Bay leaves extracts as active additive for food protective coatings

Ethanolic extracts of bay leaves were obtained using the Soxhlet method (extraction yield of 22.3 ± 1.2%) and further analyzed through different methods, thus determining the chemical composition with gas chromatography, phenolic content with the Folin–Ciocalteu technique (11.8 ± 0.4% wt.) and antioxidant power with the radical 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) method (75.06%). Furthermore, its effect on the growth of two bacteria, Escherichia coli and Bacillus cereus, and on two yeasts, Candida glabrata and Saccharomyces cerevisiae, was determined, showing a minimum inhibitory concentration of 0.65 mg/mL on the growth of B. cereus. Finally, edible films were prepared using different polymers (carboxymethyl cellulose, gum Arabic, polyvinyl pyrrolidone, and polyvinyl alcohol) containing 0, 5, 10, or 15% wt. of bay leaf extract as troubleshooting for perishable fruits, specifically for cultivated strawberry. The prepared composites presented reduced water vapor permeabilities (up to 4.3 × 10−7 g·Pa−1·m−1·h−1), high specific transparencies (≈30%/mm), as well as the effective blocking of ultraviolet radiation (>99.9%). In vivo tests showed that the most suitable treatment for strawberry protection was the impregnation with a composite comprising polyvinyl alcohol and a 15% wt. bay leaf extract, resulting in a noteworthy reduction in mass loss (22% after 6 days). It can be asserted that food packaging with the designed composites would be an effective alternative for the reduction in postharvest losses

Influence of Reynolds number on theoretical models for trailing vortices

We conduct direct numerical simulations for a NACA0012 airfoil at Reynolds numbers (Re) ranging from 300 to 7000 to determine the wake behavior behind this wing profile. We characterize the structure of the wing-tip vortex, finding a reasonable agreement with experimental results at Re=7000. In addition, we model the trailing vortex theoretically, thus obtaining the parameters for Batchelor’s and Moore and Saffman’s models. We compare the results of the best fitting for the axial vorticity and the azimuthal velocity, finding only small discrepancies. The main contribution of this research work is to study the evolution of these theoretical parameters as function of the Reynolds number. We observe that the wake becomes unstable at Re ≈1200, in agreement with previous results. These instabilities in the wake behind the wing produce a change in the trend of theoretical parameters (keywords: vortex dynamics, trailing vortices, theoretical models).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech