An experimental and theoretical study of unsteady flow (gust) effects on structures

The gust wind tunnel at IDR, Universidad Politécnica de Madrid (UPM), has been enhanced and the impact of the modification has been characterized. Several flow quality configurations have been tested. The problems in measuring gusty winds with Pitot tubes have been considered. Experimental results have been obtained and compared with theoretically calculated results (based on potential flow theory). A theoretical correction term has been proposed for unsteady flow measurements obtained with Pitot tubes. The effect of unsteady flow on structures and laying bodies on the ground has been also considered. A theoretical model has been proposed for a semi-circular cylinder and experimental tests have been performed to study the unsteady flow effects, which can help in clarifying the phenomenon.

Gust wind tunnel study on ballast pick-up by high-speed trains

This paper describes the experimental setup, procedure, and results obtained, concerning the dynamics of a body lying on a floor, attached to a hinge, and exposed to an unsteady flow, which is a model of the initiation of rotational motion of ballast stones due to the wind generated by the passing of a high-speed train. The idea is to obtain experimental data to support the theoretical model developed in Sanz-Andres and Navarro-Medina (J Wind Eng Ind Aerodyn 98, 772–783, (2010), aimed at analyzing the initial phase of the ballast train-induced-wind erosion (BATIWE) phenomenon. The experimental setup is based on an open circuit, closed test section, low-speed wind tunnel, with a new sinusoidal gust generator mechanism concept, designed and built at the IDR/UPM. The tunnel’s main characteristic is the ability to generate a flow with a uniform velocity profile and sinusoidal time fluctuation of the speed. Experimental results and theoretical model predictions are in good agreement.