Windbreaks for railway lines: Wind tunnel experimental tests

A number of tests were carried out in the Politecnico di Milano wind tunnel to study the properties of different windbreak barriers for high-speed railway lines. A possible problem with the wind tunnel testing of these devices is the need to create wide scenarios (long barriers) and achieve high Reynolds number values in order to avoid scaling problems. In this study, two experimental campaigns were performed. In the first stage, the Reynolds number sensitivity was checked through specific tests in a high-speed test section (Re-max=7x10(5)): it was found that, in the presence of barriers, the rolling moment coefficient is independent of the Reynolds number. A second experimental campaign was then carried out in a low-speed test section (Re-max=1.3x10(5)) where a very long scenario was reproduced (150 m at real scale): barriers of different types, heights and porosities were tested. To compare them, forces and pressures on the vehicle model as well as forces on the barrier were measured.