pFFT方法在波浪与结构作用中的不规则频率消除技术

对于求解波浪与大型结构物作用的pFFT方法,即预修正快速傅里叶变换方法(Pre-corrected Fast Fourier Transform),该文提出了消除"不规则频率"影响,从而保证在各频率下均可得到正确解的求解技术。该方法通过在内水面上配置源点的方法得到了唯一解的积分方程,并通过叠加物体内部积分方程而得到了便于求解的方形矩阵。算例表明:该方法能够消除"不规则频率"的影响,在整个频率内均可得到精确的计算结果;对于大型计算,在计算效率和内存空间的使用上,均较传统的高阶边界元方法有很大优势。

Removing irregular frequency in the pre-corrected FFT method for wave-structure interaction

For the pre-corrected Fast Fourier Transform method (pFFT) applied in the analysis of wave-structure interaction,a technique is applied to remove the "irregular frequencies" in the integral equation to guaranty the solution unique and correct,which is derived by arranging more source points on the inner water plane.By combining with an integral equation established for the interior problem of the body,a square matrix can be obtained which makes the equation easier to be solved.The numerical results illustrate that this method can remove the effect of irregular frequencies,and obtain accuracy results at all computation frequency.Comparing to the higher-order boundary element method,it has the advantages in reducing computing time and saving computer memory space.