Reduced-order modeling for unsteady transonic flows around an airfoil

High-transonic unsteady flows around an airfoil at zero angle of incidence and moderate Reynolds numbers are characterized by an unsteadiness induced by the von Kármán instability and buffet phenomenon interaction. These flows are investigated by means of low-dimensional modeling approaches. Reduced-order dynamical systems based on proper orthogonal decomposition are derived from a Galerkin projection of two-dimensional compressible Navier-Stokes equations. A specific formulation concerning density and pressure is considered. Reduced-order modeling accurately predicts unsteady transonic phenomena

Reduced-order modeling of transonic flows around an airfoil submitted to small deformations

A reduced-order model (ROM) is developed for the prediction of unsteady transonic flows past an airfoil submitted to small deformations, at moderate Reynolds number. Considering a suitable state formulation as well as a consistent inner product, the Galerkin projection of the compressible flow Navier–Stokes equations, the high-fidelity (HF) model, onto a low-dimensional basis determined by Proper Orthogonal Decomposition (POD), leads to a polynomial quadratic ODE system relevant to the prediction of main flow features. A fictitious domain deformation technique is yielded by the Hadamard formulation of HF model and validated at HF level. This approach captures airfoil profile deformation by a modification of the boundary conditions whereas the spatial domain remains unchanged. A mixed POD gathering information from snapshot series associated with several airfoil profiles can be defined. The temporal coefficients in POD expansion are shape-dependent while spatial POD modes are not. In the ROM, airfoil deformation is introduced by a steady forcing term. ROM reliability towards airfoil deformation is demonstrated for the prediction of HF-resolved as well as unknown intermediate configurations

Anisotropic Organised Eddy Simulation for the prediction of non-equilibrium turbulent flows around bodies

The unsteady turbulent flow around bodies at high Reynolds number is predicted by an anisotropic eddy-viscosity model in the context of the Organised Eddy Simulation (OES). A tensorial eddy-viscosity concept is developed to reinforce turbulent stress anisotropy, that is a crucial characteristic of non-equilibrium turbulence in the near-region. The theoretical aspects of the modelling are investigated by means of a phase-averaged PIV in the flow around a circular cylinder at Reynolds number 1.4×10^5. A pronounced stress–strain misalignment is quantified in the near-wake region of the detached flow, that is well captured by a tensorial eddy-viscosity concept. This is achieved by modelling the turbulence stress anisotropy tensor by its projection onto the principal matrices of the strain-rate tensor. Additional transport equations for the projection coefficients are derived from a second-order moment closure scheme. The modification of the turbulence length scale yielded by OES is used in the Detached Eddy Simulation hybrid approach. The detached turbulent flows around a NACA0012 airfoil (2-D) and a circular cylinder (3-D) are studied at Reynolds numbers 105 and 1.4×10^5, respectively. The results compared to experimental ones emphasise the predictive capabilities of the OES approach concerning the flow physics capture for turbulent unsteady flows around bodies at high Reynolds numbers

Deflection, drift and advective growth in variable-density, laminar mixing layers

Specific features of the variable-density mixing layers without gravity effects are studied using self-similar solutions to the laminar and time-evolving variant of this flow. Density variations come from either mass or temperature mixing, accounting for, in the latter case, the effect of the Mach number. The transverse profiles of the flow quantities, as well as the time evolutions of the global characteristic scales of the mixing layer, are given for a wide range of density ratio and Mach-number values. When compared to the constant-density case, it appears that most of the specificity of these flows comes from the emergence of a nonzero transverse component of the velocity. First, it produces a deflection of the flow that can be either confined in the core of the layer or global, the whole layer being tilted at an angle from the initial flow direction. In most cases, this deflection is such that some part of the higher-density fluid is "entrained" in the direction of the lower-density fluid, leaving no possibility to define a dividing streamline. Second, it leads to a shift between the density profile and the profiles of the other flow quantities. This shift scales on the time-increasing mixing-layer thickness and therefore appears as a time drift. When global deflection is present, the tilting of the layer can be shown to be equivalent to a global drift of the mixing/shear layer toward the light-fluid side of the flow. Third, transport by the transverse velocity component affects the spreading of the mixing layer, giving rise to an additional effect referred to as advective growth. Examination of the density-ratio and Mach-number effects leads to surprising results: While the momentum thickness is always observed to decrease when increasing these parameters, conventional thicknesses based on the profiles of the different variables can show opposite behaviors depending on the form of the diffusion model for the considered variable

The Index of amplitude of behavior as a measuring instrument of social ability in preschool children

In order to assess the developmental validity of the Index of Amplitude of Beha- vior (IAB) as a measuring instrument of social ability in preschool children, the varia- tion of this index was studied during an academic year in an Andalusian school. The so- cial behavior of 31 preschool children (aged five) was observed during free play period and a measure of IAB for each subject was calculated chronologically through the who- le study period. According to the data obtained in this study, 300 seconds of observation is a sufficient period of time to reliably estimate the Index of Amplitude of Behavior of a subject. An adjustment of the values of the IAB of each individual towards the mean of the IAB of all the individuals of the group was detected. This suggests that the Index of Amplitude of Behavior could be considered not only as a measuring instrument of so- cial ability, but also an useful tool to explore the effects of peer-groups in socializationEl índice de amplitud de comportamiento como instrumento de medida de la ha- bilidad social en niños preescolares. Con el objeto de evaluar la validez del Indice de Amplitud de Comportamiento (IAB) como un instrumento de medida de la habilidad so- cial de niños preescolares, se estudió la variación de dicho índice durante un año acadé- mico en un colegio andaluz. Para ello, se observó el comportamiento social de 31 niños (de 5 años de edad) en el recreo y se calculó cronológicamente durante el período de es- tudio una medida de IAB para cada sujeto. De acuerdo con los datos obtenidos, 300 se- gundos de observación se considera un período de tiempo adecuado para una estimación fiable del IAB de un sujeto. Se detectó un ajuste de los valores del IAB de cada indivi- duo a la media del IAB de todos los individuos del grupo; lo que sugiere que el IAB pue- de ser además considerado como una herramienta útil para explorar la influencia de los grupos de pares en la socialización.Peer reviewe

Evaluating the impact of an active labour market policy on employment: short- and long-term perspectives

The Labour Market Insertion Contract was an Active Labour Market Policy introduced in Spain. It was aimed at individuals who had difficulties entering the labour market, and it was introduced with the purpose of reducing the rate of unemployment. This article provides an estimation of the average impact that this contract had on the employability of individuals in the short and long term. A microeconomic analysis was carried out based on causal statistical inference by using propensity score matching and kernel and radial estimators. Data was taken from the most comprehensive database available, which is the Continuous Sample of Work Histories. Results are consistent with literature reports and show that the employability of participants was inferior to that of individuals with similar, temporary-type contracts. This research contributes to the literature by evaluating whether there was empirical evidence to support the political decision to revoke or replace this kind of direct employment programme.Junta de Andalucía proyecto SEJ-132Universidad Autónoma de ChileUniversidad de Sevilla. Departamento de Análisis Económico y Política Económic

La docencia. Evolución histórica del profesorado

Con motivo del 150 aniversario de la creación de la Escuela Normal de Cádiz, posteriormente Escuela de Formación del Profesorado de EGB, Escuela de Magisterio y, actualmente, Facultad de Ciencias de la Educación, se hace un recorrido histórico centrado en el profesorado de la misma, desde los 5 profesores iniciales hasta los más de 120 actuales. En función de los cambios legislativos que se producen históricamente, se describen los cambios en las características de las plantillas docentes, no sólo en cuanto su número, sino también en cuanto a sus características, formación y sistema de acceso

A Comparison of Experiential and Classroom Learning Models in Teaching Health Problems of the Poor

The general problem was to assess differences, if any, in selected areas of knowledge, attitudes and behavior among students exposed to a classroom model with students exposed to an experiential (community live-in} model in learning about health problems of the poor. Specific problems included: the selection of instruments, the development of methods and materials for teaching the classroom and experiential groups, and the measurement of students\u27 knowledge, attitudes, and behavior related to the poor and their health problems

AN ASSESSMENT OF TEACHERS’ COPING MANAGEMENT OF PERCEIVED STRESS AND FEAR OF THE UNKNOWN

Amidst the burgeoning research currently conducted on the effects of COVID-19, this study looks particularly at teachers’ stress and anxiety during a time of heightened global uncertainty, which also strongly affects educational processes. The paper draws on data provided through online questionnaires, and follow-up interviews with teachers at a variety of educational institutions in Japan, the Philippines, and eight other countries. Findings from 100 respondents include details regarding the extent and distribution of various behaviors and emotional tendencies gained from quantitative analysis, and additional follow up questions, all conducted online. Numerous strategies for combatting the negative impact of COVID-19 are presented, and a variety of individual responses to this predicament is stressed. The study confirms that COVID-19 is having an unprecedented impact on education, affecting not only students but teachers as well. Thus, the study aims to both assist in alleviating the negative impacts on teachers’ wellbeing and to provide helpful insights that contribute to the body of knowledge on teachers’ coping management of perceived stress and anxiety

BRAINWAVES OF EMOTION AMONG JAPANESE EFL LEARNERS AS PROOF OF THE EFFECTIVENESS OF FAMILY ENVIRONMENT MODE APPROACH (FEMA)

This paper expands the author’s recently developed EFL teaching method, the Family Environment Mode Approach (FEMA) (Ocampo, 2016), including students’ narrated endorsements, which give further insight into students learning experience in support of the method’s efficacy. The paper demonstrates that to surrender to the belief that someone has no ability to improve their English fluency obscures the heterogeneity of pathways leading to a thriving learning experience. The idea that failure is often a necessary prerequisite to success is emphasized. The study demonstrates that a combination of changing students’ mindsets to become pro-failure and FEMA is effective in helping them improve their speaking ability, and freeing them from what can seem to be a ‘cage of fear’ with regards to making mistakes. A move from a traditional classroom situation, to one where failure is embraced is shown to be a process that can alleviate or perhaps eradicate anxiety and stress, opening up the gateway of learning. The use of Necomimi (brainwave cat ears) is incorporated to help demonstrate the effectiveness of FEMA. Necomimi is a sophisticated, animatronic cat-ear headset that moves in various ways in response to how the device interprets students’ mood, measuring the brainwaves of emotion while speaking English. The paper reports that strong student support for this method was observed. At the end of the school year, most of the participating students recommended that teachers of English and other subjects adopt FEMA more widely.&nbsp