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Wingtip vortices represent a hazard for the stability of the following airplane in airport highways. These flows have been usually modeled as swirling jets/wakes, which are known to be highly unstable and susceptible to breakdown at high Reynolds numbers for certain flow conditions, but different to the ones present in real flying airplanes. A very recent study based on Direct Numerical Simulations (DNS) shows that a large variety of helical responses can be excited and amplified when a harmonic inlet forcing is imposed. In this work, the optimal response of q-vortex (both axial vorticity and axial velocity can be modeled by a Gaussian profile) is studied by considering the time-harmonically forced problem with a certain frequency ω. We first reproduce Guo and Sun’s results for the Lamb-Oseen vortex (no axial flow) to validate our numerical code. In the axisymmetric case m = 0, the system response is the largest when the input frequency is null. The axial flow has a weak influence in the response for any axial velocity intensity. We also consider helical perturbations |m| = 1. These perturbations are excited through a resonance mechanism at moderate and large wavelengths as it is shown in Figure 1. In addition, Figure 2 shows that the frequency at which the optimal gain is obtained is not a continuous function of the axial wavenumber k. At smaller wavelengths, large response is excited by steady forcing. Regarding the axial flow, the unstable response is the largest when the axial velocity intensity, 1/q, is near to zero. For perturbations with higher azimuthal wavenumbers |m| > 1, the magnitudes of the response are smaller than those for helical modes. In order to establish an alternative validation, DNS has been carried out by using a pseudospectral Fourier formulation finding a very good agreement. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

In order to provide decision-makers with analytical elements, inequity-related aspects of vaccination of children were evaluated, through an analysis of the gaps or differences in coverage levels in municipalities compared to the national level. The study was ecological and included a multiple regression analysis which included variables related to both territory and the health system. Bigger differences were found to be related to rural areas, the size of municipalities and higher density of children in the population. Smaller gaps were found to be connected to subsidized affiliation to the Health System and per capita investments in public health. As a conclusion, the authors recommend to concentrate spending in municipalities with high inequity, little urban development and little resources. Para aportar elementos analíticos a los tomadores de decisiones se analizaron los factores asociados a las inequidades en la vacunación infantil, a través del análisis de las brechas o diferencias de cobertura municipal en relación con el nivel nacional, mediante un estudio ecológico que empleó un análisis de regresión múltiple que incluyó tanto variables territoriales, como del sistema de salud. Se asociaron con el aumento de las brechas de cobertura la ruralidad, el tamaño funcional municipal, y la mayor densidad de población infantil. A su vez, disminuyen estas diferencias la afiliación subsidiada al Sistema de Salud y los recursos per cápita destinados a salud pública. Se concluye que el esfuerzo debería centrarse en municipios con mayor desigualdad, menor urbanización y recursos. Para contribuir com elementos analíticos aos tomadores de decisões se analisaram os fatores associados às inequidades na vacinação infantil, através da análise das brechas ou diferenças de cobertura municipal em relação com o nível nacional, mediante um estudo ecológico que empregou uma análise de regressão múltipla que incluiu tanto variáveis territoriais, como do sistema de saúde. Foram associados com o aumento das brechas de cobertura rural, o tamanho funcional municipal, e a maior densidade de população infantil. A sua vez, diminuem estas diferenças a afiliação subsidiada ao Sistema de Saúde e os recursos per capita destinados à saúde pública. Conclui-se que o esforço deveria concentrar-se em municípios com maior desigualdade, menor urbanização e recursos.