2018 年 84 巻 866 号 p. 18-00105
Under the existing method based on a detailed equation for evaluating the wind speed that can cause a vehicle to overturn, it is assumed that the crosswind blows the vehicle at the same wind speed uniformly over the entire length of the vehicle body along the track. However, taking into consideration the actual wind state, there is a wind speed distribution over the length of the vehicle body and there is a high possibility that the crosswind does not blow at the same wind speed over the entire length of the vehicle body. Therefore, if the wind speed distribution is considered, it becomes possible to evaluate the critical wind speed in more detail. In previous research, an evaluation formula of aerodynamic force in consideration of the wind speed distribution has been proposed with the natural wind direction assumed to be 90 degrees. On the other hand, the calculation of the wind speed that can cause a vehicle to overturn requires extending the evaluation formula so as to be applicable to the other natural wind directions. In this study we proposed, extending the existing evaluation formula, a method of calculating the critical wind speed in consideration of the spatial fluctuation of wind speed. We also evaluated the critical wind speed for the combination of the vehicle and the track constructions with the proposed method. In addition, we also evaluated the critical wind speed in accordance with changes in the height of the center of the car body from the ground and the roughness length. As a result of the evaluation, we confirmed that the critical wind speed increases by up to 1.4m/s, provided that the vehicles and railway structures are those assumed in this study.
