发展了一种模态匹配方法进行有均匀流条件下敷设声衬的二维矩形流管中声传播的计算,计算结果与NASA流管实验结果和CAA计算结果符合得很好.在此基础上,着重介绍采用求极值的变尺度法优化目标函数和给定求解范围寻找目标函数最小值两种方法进行管内未知声阻抗的提取,给出了算例验证,并分析了随机误差和已知声压点数对计算结果的影响.
A mode-match method was developed for calculating the sound propagation in two-dimensional lined rectangular flow duct with uniform flow, the prediction results agree well with the data from NASA flow duct facility and CAA calculation. Based on these, an unknown impedance extracting is implemented by applying changed-scales method to optimize object function or by pursuing a minimum of object function in a given region. The two methods are validated by some cases and the effects of random error and the number of input pressure on the results are analyzed.