设置风屏障是提高行车安全的有效措施之一,但防风效果受风屏障参数、周围环境等多种因素影响。基于同步测压方法,结合本征正交分解技术对风压测点进行加密后通过积分获得气动力,以京沪高速铁路典型高架桥和CRH2列车为背景,研究多种风屏障参数对典型车桥组合状态下中间车辆气动力和风压分布的影响。研究结果表明:测压积分可获得与天平测力精度相当的气动力;风屏障对上游列车的防风效果显著,下游列车气动特性则受之影响较小;相对而言,风屏障透风率大小对列车气动特性影响较大,高度影响较小,且二者存在一个最优组合;设置风屏障后,尽管平均气动力会减小,但最大气动力由于特征紊流的影响可能会增大,风屏障参数应通过风洞试验或数值模拟慎重选取。
Installing wind barrier is one of the effective methods to improve the security of the running train.However,the wind shielding effect is influenced by many factors,such as wind barrier parameters and its surroundings.The models of CRH2 type train and 32mpre-stressed concrete simply supported box beam viaduct at Beijing-Shanghai high-speed rail line are manufactured with geometric scale of 1:25in order to investigate the effects of wind barrier parameters,namely porosity and height,on aerodynamic forces and pressure distribution of trailing vehicles under representative combination cases of model vehicles on double tracks on the model viaduct.Based on the simultaneous pressure measurement,the aerodynamic forces are obtained by the use of the proper orthogonal decomposition technique,according to which pressure measurement points can be increased.It is shown that when the pressure taps distribution is appropriate and sufficiently dense,the steady aerodynamic forces generated by pressure complementary calculations are as accurate as those by the force test.While the aerodynamics of leeward vehicle is less affected,the effects of wind shield on the windward vehicle are significantly affected by wind barrier.In general,the effect of the porosity of wind barrier on aerodynamic characteristics is greater than that of its height,and there is an optimal combination between wind barrier porosity and height.Although the mean aerodynamic forces of vehicle will be reduced with the installation of wind barrier,the maximum aerodynamic forces may increase because of the effect of the characteristic turbulence.Therefore,wind barrier parameters should be carefully chosen in wind tunnel test or computational fluid dynamics numerical simulation.