考虑地面效应的高速列车远场气动噪声计算方法研究

为研究高速列车远场气动噪声的计算方法,根据高速列车近地面运行的实际情况,利用半自由空间的Green函数求解FW-H方程;建立考虑地面效应时的远场声学积分公式,并研究地面效应对高速列车远场气动噪声的影响.研究表明,由于存在地面效应,原来的自由声场变成了相当于真实列车声场与镜像列车声场的叠加,并且作用在镜像列车上的力源和法向运动速度与真实列车上的相同.当列车运动速度为350 km/h时,不考虑地面效应时,远场测点的等效连续A计权声压级的最大值为90.76 dB;考虑地面效应之后,远场测点的等效连续A计权声压级的最大值为94.72 dB.

Study of computational method of far-field aerodynamic noise of a high-speed train considering ground effect

In order to study the computational method of far-field aerodynamic noise of a high-speed train,based on the actual situation of high-speed trains running near the ground,the FW-H equation was solved using the semi-free-space Green's function.The far-field acoustical integral formula considering ground effect was established.The influence of ground effect on the far-field aerodynamic noise of the high-speed train was studied.Studies show that the former free sound field is equivalent to superposition of sound field of realistic train and sound field of mirror train.The force sources and normal velocities on the mirror train are the same as that of on the realistic train.When the train speed is 350 km/h,the maximum value of equivalent continuous A-weighted sound pressure level is 90.76 dB when the ground effect is not considered.When the ground effect is considered,the maximum value of equivalent continuous A-weighted sound pressure level is 94.72 dB.