本篇論文主要是針對二維的聲音輻射(acoustic radiation)和散射(scattering)場提供一個有效的解決方法。虛構的特徵頻率的困難能由合併滿足在物體表面內的某些邊界條件的輔助內部面來克服。而此過程將可導出一套獨特地可解決的邊界積分方程式。分佈有未知強度的單聲源(monopoles)在物體和內部表面產生一個簡單源公式。修飾的邊界積分方程式能進一步轉換成常積分方程式，即只包含非奇異核(nonsingular kernels) 。這個成就允許直接的應用標準求積分公式在整個積分區域，也就是排列點恰好在積分點。內部表面的選擇並不困難，此外，只有少許符合的內部節點對計算的結果來說已是足夠的。數值的計算由聲學上全硬的橢圓柱和長方柱組合聲音的輻射和散射。對照解析解，數值結果證明這個解決方法的效率和正確性。

This paper presents an effective solution method for predicting acoustic radiation and scattering fields in two dimensions. The difficulty of the fictitious characteristic frequency is overcome by incorporating an auxiliary interior surface that satisfies certain boundary condition into the body surface. This process gives rise to a set of uniquely solvable boundary integral equations. Distributing monopoles with unknown strengths over the body and interior surfaces yields the simple source formulation. The modified boundary integral equations are further transformed to ordinary ones, i.e. containing nonsingular kernels only. This implementation allows directly applying standard quadrature formulas over the entire integration domain; that is, the collocation points are exactly the positions at which the integration points are located. Selecting the interior surface is an easy task; moreover, only a few corresponding interior nodal points are sufficient for the computation. Numerical calculations consist of the acoustic radiation and scattering by acoustically hard elliptic and rectangular cylinders. Comparisons with analytical solutions are made. Numerical results demonstrate the efficiency and accuracy of the current solution method.

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