Resumen Se presenta una revisión de literatura de los túneles de viento con mayor relevancia en la investigación sobre energía eólica. Se realizó una búsqueda sistemática en la base de datos de Web of Science (WoS) en la que se obtuvieron 93 artículos que fueron filtrados para el periodo 2016-2020 y mediante distintos criterios de relevancia. Los artículos permitieron identificar 34 túneles alrededor del mundo. Se seleccionaron los ocho túneles de viento con mayor volumen de publicación y se presentan los estudios realizados en estos. Los principales temas encontrados en la revisión tratan sobre turbinas de eje horizontal y vertical, estelas, perfiles aerodinámicos y recurso eólico. Esta revisión tiene como objetivo servir de referencia para los investigadores en energía eólica que requieren realizar experimentos en túneles de viento.

Abstract A literature review about the most relevant wind tunnels in wind energy research is presented. A systematic search was carried in the Web of Science (WoS) database in which 93 papers were filtered by year from 2016 to 2020 and different relevance criteria. From the papers, 34 different wind tunnels were identified around the world. The eight tunnels with the most publications were selected and the research carried in them is presented. The main topics found are research in horizontal wind turbines (HAWT), vertical wind turbines (VAWT), turbine wake, airfoils and wind resource. This review has the objective to serve as a reference guide to researchers in wind energy that require to do experimentation in a wind tunnel.

Biodiesel, unlike diesel, is highly susceptible to autoxidation. This autoxidation is a major concern for a biodiesel producer. Various methods have been developed to estimate the degree of oxidative stability of biodiesel. These methods are useful to compare and estimate the oxidative stability between different biodiesel samples. However, an absolute value of the oxidative state will be more useful. In this study, we describe a method of estimating a figure that can be used as an indicator of the oxidation level. This indicator was determined from the thermal decomposition curve of biodiesel, as obtained from the thermogravimetric test. Biodiesel from waste cooking oil was oxidized at 80, 100 and 120 ºC using different exposure areas (19.6, 63.6, and 153.9 cm2). The percentage of oxidation, measured from low (80 ºC, 19.6 cm2) to highly aggressive conditions (120 ºC, 153.9 cm2), was in the range of 0.4 ± 0.1 and 23.5 ± 3.3. Kinematic viscosity was also measured for the oxidized samples, and a strong correlation (R2=0.96) was observed between the percentage of oxidation products and kinematic viscosity. In addition, the oxidative effect of temperature and area of exposure on the biodiesel samples was confirmed by ultraviolet spectroscopy.