Determinación de propiedades aerodinámicas de la jabalina mediante dinámica de fluidos computacional. [Determination of aerodynamic properties of javelin by means of computational fluid dynamics].

Resumen

Durante el vuelo de la jabalina su interacción con el aire circundante presenta una importancia relevante, lo cual es caracterizado por los coeficientes de sustentación y arrastre y por la posición del centro de presiones. Habitualmente estos parámetros son determinados en túneles de viento con la envergadura requerida para albergar un implemento de estas dimensiones, siendo complicado evitar interferencias de los medios de sostén, así como lograr la medición experimental de los campos de presiones y velocidades en las proximidades de la jabalina. Para solventar estas dificultades, en el trabajo se aborda la simulación computarizada de la interacción jabalina-aire empleando herramientas de Dinámica de Fluidos Computacional (CFD). Modelos digitalizados tridimensionales de jabalinas con peso y dimensiones oficiales, fueron sometidos a corriente de aire, siguiendo un diseño experimental con cinco niveles de velocidad relativa entre el aire y la jabalina y ocho niveles de ángulo de ataque. Como resultado se obtuvieron las curvas de ajuste de los coeficientes de arrastre y sustentación vs. el ángulo de ataque para ambos tipos de jabalina. Asimismo fue determinada la posición del centro de presiones y la magnitud y dirección del momento de rotación en función de la velocidad relativa entre el aire y la jabalina para diferentes ángulos de ataque. Los resultados otenidos son de relevante importancia durante la elaboración de modelos matemáticos de simulación del vuelo de la jabalina, que pueden ser empleados por entrenadores y atletas con vista al perfeccionamiento de los parámetros iniciales del lanzamiento y la obtención de mejores marcas.

Abstract

During the flight of the javelin its interaction with the surrounding air presents a relevant importance, which is characterized by the coefficients of lift and drag and by the position of the center of pressures. Usually these parameters are determined in wind tunnels with the required span to accommodate an implement of these dimensions, being difficult to avoid interferences of the support means, as well as achieving the experimental measurement of the fields of pressures and velocities in the vicinity of the javelin. To solve these difficulties, in the present work the computerized simulation of the javelin-air interaction using Computational Fluid Dynamics (CFD) tools is carried out. Three-dimensional models of javelins with official weight and dimensions, were subjected to an air stream, with five levels of relative speed between the air and the javelin and eight levels of attack angle. As a result, the adjustment curves of the drag and lift coefficients vs. the angle of attack for both types of javelin were obtained. Likewise, the position of the center of pressures and the magnitude and direction of the pitching moment as a function of the relative velocity between the air and the javelin (masculine modality) for different angles of attack were determined. The results obtained are of relevant importance for the development of mathematical models of simulation of the javelin flight, which can be used by coaches and athletes with a view to improving the release parameters in order to obtain better performance.

https://doi.org/10.5232/ricyde2019.05602

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