DIFFRACTION COEFFICIENTS FOR FLAT-BOTTOMED HOLES FROM 3-D FINITE-DIFFERENCE CALCULATIONS

被引:3
|
作者
TEMPLE, JAG
机构
[1] AEA Industrial Technology, Materials and Manufacturing Division, Theoretical Studies Department, Oxfordshire OX11 0RA
关键词
HOLES; FINITE DIFFERENCE MODEL; DIFFRACTION;
D O I
10.1016/0041-624X(93)90027-W
中图分类号
O42 [声学];
学科分类号
070206 ; 082403 ;
摘要
Calculations have been performed with a finite difference model Swam3d to predict the time-dependent scattering in three spatial dimensions from the edge of a flat-bottomed hole. It is shown that 'diffraction coefficients' can be defined for non-normal incidence on flat-bottomed holes and that these can be calculated using 3-D finite difference techniques. It is concluded that it is appropriate to use diffraction coefficients obtained from the canonical problem of scattering from a 270-degrees vertex and to multiply these by a 'curvature term' which depends solely on the angles of incidence and scattering, the radius of curvature of the edge and on the ranges from the transmitter to the receiver, as expected from the geometrical theory of diffraction. Comparisons of results for this curvature term, determined from finite difference calculations, are made with an analytical expression. Good agreement is achieved away from specular directions. A problem exists with determining diffraction coefficients and the curvature term near specular reflection directions with the finite difference model. A solution is proposed but not tested.
引用
收藏
页码:3 / 12
页数:10
相关论文
共 50 条
  • [41] 3-D versus 2-D finite-difference seismic synthetics including real surface topography
    Hestholm, SO
    Ruud, BO
    Husebye, ES
    PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 1999, 113 (1-4) : 339 - 354
  • [42] 3-D acoustic reverse-time migration with a stress-velocity finite-difference method
    Kalantzis, F
    Vafidis, A
    Kanasewich, ER
    JOURNAL OF SEISMIC EXPLORATION, 1996, 5 (03): : 229 - 244
  • [43] Numerical simulation of 3-D seismic wave based on alternative flux finite-difference WENO scheme
    Xu, Tianhong
    Zhang, Zhenguo
    GEOPHYSICAL JOURNAL INTERNATIONAL, 2024, 238 (01) : 496 - 512
  • [44] Efficient 3-D controlled-source electromagnetic modelling using an exponential finite-difference method
    Jaysaval, Piyoosh
    Shantsev, Daniil V.
    de Ryhove, Sebastien de la Kethulle
    GEOPHYSICAL JOURNAL INTERNATIONAL, 2015, 203 (03) : 1541 - 1574
  • [45] Huygens Subgridding for 3-D Frequency-Dependent Finite-Difference Time-Domain Method
    Abalenkovs, Maksims
    Costen, Fumie
    Berenger, Jean-Pierre
    Himeno, Ryutaro
    Yokota, Hideo
    Fujii, Masafumi
    IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 2012, 60 (09) : 4336 - 4344
  • [46] Efficient Implementation for 3-D Laguerre-Based Finite-Difference Time-Domain Method
    Duan, Yan-Tao
    Chen, Bin
    Fang, Da-Gang
    Zhou, Bi-Hua
    IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, 2011, 59 (01) : 56 - 64
  • [47] A finite-difference method for studying thermal deformation in a 3-D microsphere exposed to ultrashort pulsed lasers
    Du, Xudong
    Dai, Weizhong
    Wang, Pan
    NUMERICAL HEAT TRANSFER PART A-APPLICATIONS, 2008, 53 (05) : 457 - 484
  • [48] A 3-D FINITE-DIFFERENCE ALGORITHM FOR DC RESISTIVITY MODELING USING CONJUGATE-GRADIENT METHODS
    SPITZER, K
    GEOPHYSICAL JOURNAL INTERNATIONAL, 1995, 123 (03) : 903 - 914
  • [49] Analysis of higher-order, finite-difference schemes in 3-D reverse-time migration
    Wu, WJ
    Lines, LR
    Lu, HX
    GEOPHYSICS, 1996, 61 (03) : 845 - 856
  • [50] APPLICATION OF 3-D FINITE-DIFFERENCE METHOD FOR INDUCTANCE CALCULATION OF AIR-CORE COILS SYSTEM
    ZAKRZEWSKI, K
    LUKANISZYN, M
    COMPEL-THE INTERNATIONAL JOURNAL FOR COMPUTATION AND MATHEMATICS IN ELECTRICAL AND ELECTRONIC ENGINEERING, 1994, 13 (01) : 89 - 92