Measuring the oncoming flow that operational freight-trains experience using the DLR FR8-LAB

Abstract

The DLR FR8-LAB is a self-contained swap-body container, equipped with an on-board power supply, data acquisition system and remote-access communication. The oncoming flow is derived from the surface pressure measurements on the FR8-LAB container’s front/rear/side surfaces and a calibration developed in a 1:15 scaled closed-return wind-tunnel experiment. The wind-tunnel model of the container was statically yawed over a range of −90:90°, mapping the relationship between changing surface-pressure and yaw angles. This relationship is used to infer the oncoming flow characteristics – until now, uncharacterized – that the FR8-LAB experiences in real-world operation, through application of the calibration to the measured transient surface-pressure. Oncoming flow conditions can be used to discover and characterize the real-world operating conditions at specific locations where aerodynamics is important, as well as input into aerodynamic/multi-body models to assess the risk of overturning, and modelled in simulations/experiments. Measurements on operational freight trains - validated against ultrasonic anemometers - have demonstrated that the FR8-LAB can be used to not only determine peak pressure loads and their resulting forces and moments, but also as a multi-hole dynamic-pressure probe to infer the oncoming flow conditions that freight trains experience.