Predicting the precise impacts of climate change on extreme winds remains challenging, yet strong storms are widely expected to occur more frequently in a warming climate. Wind barriers are commonly used on bridges to reduce aerodynamic loads on trains through blocking effects. This study develops a novel wind barrier based on Tesla valves, which not only blocks incoming flow but also dissipates mechanical energy through fluid collision. To demonstrate this energy-dissipation capability, a Tesla plate is placed in a circular duct to examine its influence on pressure drop. Experimental tests and numerical simulations comparing a Tesla channel and a straight channel of equal porosity show that the Tesla configuration produces a substantially higher pressure drop. Validated simulations are then used to conduct a parametric study to optimize the design. By varying the channel ratio, diversion angle, number of dissipation units, and porosity, velocity–pressure-drop relationships for different Tesla plates are obtained. The results show that larger channel ratios, larger diversion angles, and more dissipation units, combined with lower porosity, all increase pressure drop and thus enhance energy dissipation. Finally, the aerodynamic coefficients of a high-speed train on a bridge deck equipped with a Tesla-type barrier are evaluated and compared with those for a traditional straight-channel barrier. The Tesla-type barrier reduces the train’s lateral force coefficient to only 15%–25% of that produced by the traditional barrier, and it generates an additional stabilizing force that further improves running safety.