Cross-wind effects on a vehicle crossing the wake of a bridge pylon

The description of the aerodynamic cross-wind effect that occurs on a long vehicle, when it crosses the wake of a bridge tower will be analyzed both considering and neglecting the adoption of wind barriers close to tower. Wind tunnel tests are used to measure the aerodynamic loads and the surface pressure distribution on a 1:40 scale model. The presence of wind shielding near the tower produces an unexpected change in the sign of the lateral force and of the overturning moment. A description of the aerodynamic phenomenon is proposed relying on the measured force and pressure data, and on flow visualization.