Karimi Mahmoud, Croaker Paul, Kinns Roger, Kessissoglou Nicole
School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia.
J Acoust Soc Am. 2017 May;141(5):2997. doi: 10.1121/1.4982201.
A periodic boundary element technique is implemented to study the noise reduction capability of a plate with a serrated trailing edge under quadrupole excitation. It is assumed for this purpose that the quadrupole source tensor is independent of the trailing edge configuration and that the effect of the trailing edge shape is to modify sound radiation from prescribed boundary layer sources. The flat plate is modelled as a continuous structure with a finite repetition of small spanwise segments. The matrix equation formulated by the periodic boundary element method for this 3D acoustic scattering problem is represented as a block Toeplitz matrix. The discrete Fourier transform is employed in an iterative algorithm to solve the block Toeplitz system. The noise reduction mechanism for a serrated trailing edge in the near field is investigated by comparing contour plots obtained from each component of the quadrupole for unserrated and serrated trailing edge plate models. The noise reduction due to the serrated trailing edge is also examined as a function of the source location.
采用周期边界元技术研究了在四极激励下具有锯齿形后缘的平板的降噪能力。为此，假设四极源张量与后缘构型无关，并且后缘形状的影响是改变来自规定边界层源的声辐射。平板被建模为具有小展向段有限重复的连续结构。通过周期边界元法为该三维声散射问题建立的矩阵方程表示为块托普利兹矩阵。在迭代算法中采用离散傅里叶变换来求解块托普利兹系统。通过比较从无锯齿和锯齿后缘平板模型的四极各分量获得的等高线图，研究了近场中锯齿后缘的降噪机制。还研究了锯齿后缘引起的降噪作为源位置的函数。
