Acoustic finite-difference modeling beyond conventional Courant-Friedrichs-Lewy stability limit:Approach based on variable-length temporal and spatial operators  

作　　者：Hongyu Zhou Yang Liu Jing Wang 

机构地区：[1]State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China [2]Karamay Campus China University of Petroleum(Beijing),Karamay 834000,China

出　　处：《Earthquake Science》2021年第2期123-136,共14页地震学报（英文版）

基　　金：the National Natural Science Foundation of China(No.41874144);the Research Foundation of China University of PetroleumBeijing at Karamay(RCYJ2018A-01-001).

摘　　要：Conventional finite-difference(FD)methods cannot model acoustic wave propagation beyond Courant-Friedrichs-Lewy(CFL)numbers 0.707 and 0.577 for two-dimensional(2D)and three-dimensional(3D)equal spacing cases,respectively,thereby limiting time step selection.Based on the definition of temporal and spatial FD operators,we propose a variable-length temporal and spatial operator strategy to model wave propagation beyond those CFL numbers while preserving accuracy.First,to simulate wave propagation beyond the conventional CFL stability limit,the lengths of the temporal operators are modified to exceed the lengths of the spatial operators for high-velocity zones.Second,to preserve the modeling accuracy,the velocity-dependent lengths of the temporal and spatial operators are adaptively varied.The maximum CFL numbers for the proposed method can reach 1.25 and 1.0 in high velocity contrast 2D and 3D simulation examples,respectively.We demonstrate the effectiveness of our method by modeling wave propagation in simple and complex media.

关 键 词：acoustic wave equation FINITE-DIFFERENCE stability condition Courant-Friedrichs-Lewy numbers variable length. 

分 类 号：P631.4[天文地球—地质矿产勘探]