Abstract An approach based on the time-domain equivalent source method (TESM) is developed for the indoor prediction of the pass-by noise of a vehicle in a small-scale semi-anechoic chamber. In the approach, a vehicle drives on a chassis dynamometer, and a number of microphones are distributed around the vehicle to measure the pressure radiated by the vehicle in the near field. Based on the idea of TESM, the sound sources generated by the vehicle are modeled by a series of time-domain equivalent sources, and the sound radiated from these sources to the microphones is depicted by the half-space Green’s function that takes the reflections from the rigid ground into account. To evaluate the pass-by noise, the strengths of equivalent sources are first solved by using the measured pressures as the input of TESM, and then the pressures on the target points specified by the ISO 362-3 Standard are reconstructed by the superposition of sound fields generated by the equivalent sources. Finally, the sound pressure level (SPL) of the pass-by noise can be calculated from the reconstructed pressures. In particular, the proper arrangement scheme for the equivalent sources is investigated in numerical simulations to ensure the prediction accuracy. Numerical and experimental results demonstrate that the proposed approach can effectively predict the SPL of the pass-by noise of a vehicle for both constant-speed and accelerated test conditions in a small-scale semi-anechoic chamber.

中文翻译：

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基于时域等效源法的车辆通过噪声室内预测方法

摘要 提出了一种基于时域等效源法（TESM）的小规​​模半消声室车辆通过噪声室内预测方法。该方法中，车辆行驶在底盘测功机上，车辆周围分布多个麦克风，用于测量车辆在近场辐射的压力。基于TESM的思想，车辆产生的声源由一系列时域等效源建模，从这些源辐射到麦克风的声音由半空间格林函数描述，该函数从考虑到刚性地面。为了评估通过噪声，首先通过使用测量的压力作为 TESM 的输入来求解等效源的强度，然后通过等效源产生的声场的叠加来重建 ISO 362-3 标准规定的目标点上的压力。最后，通过噪声的声压级 (SPL) 可以从重建的压力中计算出来。特别是在数值模拟中研究了等效源的适当布置方案，以确保预测精度。数值和实验结果表明，所提出的方法可以有效地预测小规模半消声室中恒速和加速测试条件下车辆通过噪声的声压级。可以从重建的压力计算通过噪声的声压级 (SPL)。特别是在数值模拟中研究了等效源的适当布置方案，以确保预测精度。数值和实验结果表明，所提出的方法可以有效地预测小规模半消声室中恒速和加速测试条件下车辆通过噪声的声压级。可以从重建的压力计算通过噪声的声压级 (SPL)。特别是在数值模拟中研究了等效源的适当布置方案，以确保预测精度。数值和实验结果表明，所提出的方法可以有效地预测小规模半消声室中恒速和加速测试条件下车辆通过噪声的声压级。