预修正快速傅里叶变换方法在波浪绕射和辐射问题中应用  

Applications of precorrected-FFT method to wave diffraction/radiation problems

作　　者：姜胜超[1] 勾莹 滕斌[1] 沈洁[1] 文君锋[1] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《海洋工程》2010年第4期61-69,共9页The Ocean Engineering

基　　金：国家自然科学基金资助项目(10772040;50921001);国家科技重大专项资助课题(2008ZX05026-02-02)

摘　　要：在波浪对海上建筑物绕射和辐射问题的计算中,面元法被广泛使用,但由于传统面元法的存储量和计算量均为未知量的平方量级,很难满足大范围多未知量问题的计算需要。采用预修正快速傅里叶变换方法(pFFT方法),使计算量与存储量都降低到未知量的线性量级。以淹没圆球与漂浮圆柱两个典型算例为基础,通过不同未知量时pFFT方法与传统面元法的计算量与存储量的对比,以及pFFT方法自身各步骤计算时间的对比,研究了不同网格方案的选取对pFFT方法计算量和存储量的影响,推荐根据未知量个数采用计算时间最小化原则选取pFFT网格参数。Constant panel method（CPM） has been widely applied in the field of diffraction and radiation problems,but it is still difficult to resolve the large-scale problems because of computer storage and computing cost of O（N2）.In this paper,a pre-corrected Fast Fourier Transform method（pFFT） is developed to reduce the computing cost and computer storage to O（N） order.Numerical examinations show that the present method has more evident advantages in saving memory and computing cost,especially for large-scale problems,than the traditional CPM.According to the comparison between pFFT and traditional CPM with different numbers of unknowns and the analysis of computing cost at different parts of pFFT method,the efficiency of pFFT method of different mesh variable is discussed.From the results the optimal variable of pFFT mesh was recommended to minimize time lost.

关 键 词：面元法 预修正快速傅里叶变换方法 计算效率 波物相互作用 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]