“…The wind pressures on the windward surface of the train increase with the curvature increases, and hardly fluctuate in the vertical direction. The pressure on the bottom and leeward surface of the train is less affected by the wind barrier, which is consistent with existing results by Gu et al [9] and He et al [12].…”
Section: Effects Of the Curved Wind Barrier On The Aerodynamic Charac...supporting
confidence: 92%
“…High-speed trains running in a strong crosswind environment are prone to accidents, such as overturning and derailment, which cause heavy economic losses and casualties. The wind barrier can significantly reduce the wind speed in the train running area and ensure the running safety of the train, which is an economical and efficient wind protection measure [5][6][7][8][9].…”
Wind barriers can effectively reduce the risk of overturning and derailment of high-speed trains running on a bridge under crosswind. However, it can adversely affect the wind resistance of the bridge. There are few studies on the aerodynamic performance of curved wind barriers. In this paper, the effects of curved wind barriers with four curvatures (0, 0.2, 0.35, and 0.50) and different train-bridge combinations on the crosswind aerodynamic characteristics of a train-bridge system are investigated. The results show that the curved wind barrier can significantly reduce the wind speed below a certain height on the bridge deck. The curved wind barrier with small curvature can better reduce the aerodynamic force of the train; however, it greatly increases the aerodynamic force of the bridge. A wind barrier with a curvature of 0.35 is recommended because it takes into account the aerodynamic characteristics of the train and bridge at the same time. The porosity of a wind barrier greatly influences the aerodynamic performance of the train on the track of the windward side of the bridge, while the wind barrier has little effects on the train on the track of the leeward side of the bridge. The aerodynamic performance of the train on the track of the windward side of the bridge is less affected by whether or not a train on the track of the leeward side of the bridge is present.
“…The wind pressures on the windward surface of the train increase with the curvature increases, and hardly fluctuate in the vertical direction. The pressure on the bottom and leeward surface of the train is less affected by the wind barrier, which is consistent with existing results by Gu et al [9] and He et al [12].…”
Section: Effects Of the Curved Wind Barrier On The Aerodynamic Charac...supporting
confidence: 92%
“…High-speed trains running in a strong crosswind environment are prone to accidents, such as overturning and derailment, which cause heavy economic losses and casualties. The wind barrier can significantly reduce the wind speed in the train running area and ensure the running safety of the train, which is an economical and efficient wind protection measure [5][6][7][8][9].…”
Wind barriers can effectively reduce the risk of overturning and derailment of high-speed trains running on a bridge under crosswind. However, it can adversely affect the wind resistance of the bridge. There are few studies on the aerodynamic performance of curved wind barriers. In this paper, the effects of curved wind barriers with four curvatures (0, 0.2, 0.35, and 0.50) and different train-bridge combinations on the crosswind aerodynamic characteristics of a train-bridge system are investigated. The results show that the curved wind barrier can significantly reduce the wind speed below a certain height on the bridge deck. The curved wind barrier with small curvature can better reduce the aerodynamic force of the train; however, it greatly increases the aerodynamic force of the bridge. A wind barrier with a curvature of 0.35 is recommended because it takes into account the aerodynamic characteristics of the train and bridge at the same time. The porosity of a wind barrier greatly influences the aerodynamic performance of the train on the track of the windward side of the bridge, while the wind barrier has little effects on the train on the track of the leeward side of the bridge. The aerodynamic performance of the train on the track of the windward side of the bridge is less affected by whether or not a train on the track of the leeward side of the bridge is present.
“…Furthermore, wind barriers significantly reduced aerodynamic vehicle forces while increasing bridge aerodynamic forces [15]. The sheltering output of a train above a railway bridge and the variation laws of flow field structure leeward a corrugated wind barrier with different bending angles were investigated, and the result showed that the lateral force and overturning moment of the barrier decreased as the bending angle increased, while there were no noticeable improvements in the lift force [16].…”
Trains running on a bridge face more significant safety risks. Based on the Unsteady Reynolds-Averaged Navier–Stokes turbulence model, a three-dimensional Computational Fluid Dynamics computational model of the train–bridge–wind barrier was proposed in this study to measure the transient aerodynamic load of the train. The transient aerodynamic load was input into the wind–train–bridge coupling dynamic system to perform dynamic analysis of running safety. Significant fluctuations in the aerodynamic coefficients were found when the train entered and exited the wind barrier due to the dramatic change in flow pattern. The maximum value of the derailment coefficient decreased with the height of wind barriers, which hardly affected the wheel load reduction rate. The 2 m high wind barrier had no evident influence on the running posture of a general high-speed train, while the 4 m high wind barrier was proven to have better protection. Over-protection was found with an even higher wind barrier.
“…of the hole plate-type sand barrier. For example, Gu et al 14 studied the windproof performance of sand barriers with different waveforms, and determined that the wind fence with a bending angle of 60° has reliable deceleration performance and lower aerodynamic coefficient, and made a good trade-off between the windbreak performance of sand barriers and the increase of bridge load. Jing et al 15 conducted numerical simulations and wind tunnel experiments on sleeper-rail sand retaining walls with different porosities based on the FLUENT Euler unsteady model to study the effect of the retaining walls on wind and sand.Figure 1.(a) inclined inserting-type windbreak wall; (b) hole plate-type sand barrier.…”
In this paper, a new double-row sand barrier combined inclined inserting-type and hole plate-type sand barrier is proposed. Based on the Euler two-fluid unsteady model, the protection effect and flow field characteristics of the new sand barrier with different spacings are numerically simulated. The results show that the new sand barrier proposed in this paper has better wind resistance than the double-row hole plate-type sand barrier. The new sand barrier with spacing of 1H provides the longest effective protection distance and better wind protection. And the large spacing increases the air flow across the second-row hole plate-type sand barrier, which will reduce the protective effect of the new combined sand barrier. In addition, the windproof efficiency of the first-row inclined inserting-type sand barrier is 50%, and the windproof efficiency of the second-row hole plate-type sand barrier is 96%. It can be seen that the windproof efficiency of the double-row sand barrier is not twice that of the single-row sand barrier. Taking into account the strong wind and sand environment in Northwest China, the sand resistance effect of the new sand barrier is studied in this paper. The results show that the new sand barrier has better sand resistance effect, so that the sand is mainly deposited in the middle of the new double-row sand barrier and the windward side of the first-row sand barrier, while less deposited in the leeward side of the second-row sand barrier. It indicates that the first row of sand barrier plays the main sand resistance role.
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