Index 42, VIII absorbing boundary conditions (ABC), 21–23, 38, 89, 101, 102, 123, 133, 145–166, 168, 197, 198, 231 approximate local, 156 high–order, 23, 145, 159, 161–164 non–local, 227, 359 absorption–coefficient, 499 admittance matrix, 359, 360, 530 aeroacoustics, 115–142 anechoic boundary condition, see absorbing boundary conditions (ABC) Arnoldi method, 106, 335–337, 339 Atkinson–Wilcox theorem, 209, 210, 213 balance of momentum, 2–4, 7, 120, 123, 373, 529 BEM discretization collocation, 1, 11–21, 23, 28, 309–386, 389, 411–435, 448, 458, 477, 506, 507, 520, 522 Galerkin, 1, 11–21, 28, 341, 345, 347, 418, 435–458, 507, 519–546 Hermitian, 16, 21, 435–458, 519–546 symmetric, see Hermitian Nystr¨om, 13, 345 benchmark, 22–23, 99, 219–222, 435, 437, 453, 489 Bessel function, 128, 347, 415, 467, 471, 502 boundary conditions admittance, 8, 12–16, 21, 26, 28, 61, 66, 103, 111, 112, 156, 200, 201, 234, 275, 277, 284, 317, 326, 359, 360, 396, 398, 401, 412, 436, 442, 452–455, 457–494, 523, 529, 533, 535, 550, 552, 560, 567 Dirichlet, 8, 50, 51, 70, 71, 182, 187, 189, 263, 412, 497, 498, 552 impedance, see admittance Neumann, 8, 38, 49, 70, 177, 234, 323, 412, 413, 415, 477, 497, 498, 523, 526, 531, 552 Robin, 8, 111, 323, 466, 497, 498, 552 boundary elements, 310, 311 continuous, 309–332, 370, 371, 418, 419, 423, 425, 427–429, 432, 506 discontinuous, 12, 309–332, 360, 370, 371, 418, 423, 425, 427, 428 Bubnov–Galerkin formulation, 205 bulk–reacting material, 367–375, 382 bulk–reacting sound absorbing material, see bulk–reacting material Burton and Miller formulation, 310, 340– 345, 411–434, 478, 519, 522–523, 531, 535 CBEM, 460, 480, 488, 489, 491 Chebychev approximation, 153, 154 CHIEF, 21, 411–434, 453, 457, 477, 478 enhanced, 417–418 SuperCHIEF, 417, 418 weighted residual, 417, 418 with square matrix, 416–417, 427, 431 cluster tree, 354–362, 525, 526 Combined Helmholtz Integral Equation Formulation, see CHIEF 574 Index complex distance, 472, 473, 481 complex eigenfrequencies, 227, 278, 453 complex–source–point–BEM, see CBEM complexity estimate, VIII, 22, 23, 71–74, 76, 82–84, 95, 97, 99, 108–109, 320, 333, 336–340, 345, 346, 352–362, 381, 392–395, 402–404, 515, 519, 523, 526 condition number, 96, 100, 184, 185, 220, 222, 223, 235, 237, 239, 240, 417, 418, 531, 537, 555 conservation of mass, 2–4, 6, 7, 171 constitutive equation, 5–7, 498 convergence behavior, 96, 105, 333, 337, 340–344, 460, 466–467, 531 convergence rate, 66, 191, 254, 274, 276, 322, 421 exponential, 70, 176 convolution integral, 224, 495, 497, 500, 507, 511, 514 convolution quadrature method (CQM), 495–497, 507–509, 511, 512, 514–515 CPU time, see complexity estimate Deep Thought, VIII Dirac delta function, 9, 13, 17, 438, 463, 468, 500, 504 Dirichlet problem, see Dirichlet boundary conditions Dirichlet–to–Neumann boundary condition, see DtN map Dirichlet–to–Neumann map, see DtN map Dirichlet–to–Neumann operator, see DtN map discontinuous BEM, see discontinuous boundary elements enrichment method, 52 FEM, 39, 52 Galerkin, 52, 77, 81, 119 dispersion, VII, 37–56, 66, 67, 116, 162, 399–402 displacement formulation of the FEM, 20, 254 displacement potential, 253–256, 258, 259 DtN boundary, 104 DtN condition, 102 DtN map, 102–105, 111, 156, 168, 198, 310 dynamic stiffness matrix, 391–394, 403, 404, 528, 530, 531, 536 eigenvalue problem, 96, 254, 269–271, 387, 388, 392, 394, 401, 402, 406 elastoacoustic problem, see fluid structure interaction elements per wavelength, 23, 71, 72, 84, 105, 239, 309, 310, 318, 329, 330 energy boundary element method (EBEM), 288, 290, 304 energy finite element method (EFEM), 287–306 error dispersion, 37–56, 66, 67 pollution, 37–56, 58, 198, 309, 321, 323, 330 relative, 64, 65, 100, 101, 105–107, 109–112, 184, 235, 274, 316, 392, 421, 422 error estimate, 45–47, 105–109, 169, 176, 193, 557 error estimation, see error estimate Euler equation, 4–8, 79, 81, 119, 199, 523 examples acoustic horn, 198, 200–202, 236 acoustic lining, 359, 360, 375, 380, 396–400, 406 aircraft interior, 559 amphitheatre, 22, 495, 497, 509–513 open elliptic, 185 anechoic chamber, 22, 359, 360 auditorium, 341–343 blowout coil, 71, 72 cat’s eye, 411, 413, 420, 422–428, 431 copying machine, 559 cylinders (flow induced), 130–140 double–slit interference experiment, 185–187 duct, 200, 220, 221, 309, 311, 316–325, 328–330, 380, 387, 390, 392, 405, 406, 508, 509, 548 engine, 22, 241–247, 343–345, 411, 413, 428–432, 559–565, 568 expansion chamber, 390, 396–406, 519, 532–534 foothills model, 84, 85 hearing simulation, 22, 110–112 heavy equipment cap, 288 front window, 302–304 rear window, 300–303 L–shape test model, 531, 532 Index muffler, 367–387, 532–534 printer, 559 refrigerator compressor, 559 reverberation chamber, 22, 58, 65–67 sedan cabin compartment, 22, 309, 311, 316, 326–330, 559 silencer, 367–386, 389, 395–404 sphere, 17, 218–226, 411, 415, 418–422, 431, 453–455, 464, 476, 478, 488, 490, 491, 502 spherical piston, 225–227 submarine, 22, 145, 146, 519, 540–542 vacuum cleaner, 22, 559–568 vehicle interior, see sedan cabin compartment vibrating box with rib, 455–457 exponential integral, 475, 476, 490 fast multipole analysis (FMA), 21, 38, 333–366, 519–546 fast multipole method (FMM), see fast multipole analysis (FMA) finite elements hierarchical, 58, 66–73 Lagrangian, 23, 57, 68, 217 mixed spectral, 58, 73–84 natural cubic splines, 64 flow effects, 121, 395 flow induced noise, 119, 122, 123, 127, 130–140 flow noise, 116, 567 fluid structure interaction, 2, 21, 253–286, 389, 436, 461, 519–546 mass coupling, 258, 259, 262, 267 Mortar coupling, 538–539 potential/displacement formulation, 259 pressure/displacement formulation, 257, 259, 262, 274 pure displacement formulation, 253, 255, 258, 260, 262, 264, 268, 274, 275, 279–284 stiffness coupling, 259 strong coupling, 519, 521, 529–530, 535, 542 weak coupling, 519, 531–532, 534 Fourier transformation, 126, 162, 224, 356, 357, 499–501, 504, 508, 515, 526, 549, 550 Fourier–Laplace transform, 193 575 galaxy, VIII Galerkin–gradient/least squares method (GGLS), 51 Galerkin/least squares method (GLS), 51 Gaussian elimination, 334, 338, 394 general Kirchhoff–equation for a moved body, 505 Generalized finite element method (GFEM), 51 Green’s function, 17, 50, 287, 373, 459, 462, 486–491, 551 complex source point, see CBEM free–space, 9, 119, 370, 413, 415, 419, 462, 465 half–space, 459–476, 480, 491, 492 hard–wall, 119 modified, 419, 420 normal derivative, 413, 482–486 h–FEM, 71–73 half–space, 151, 179, 406, 459–494, 497 fundamental solution in time–domain, 502 Hankel function, 102, 156, 208, 347, 460, 469, 524 Hankel transform, 467, 468 hierarchical finite element basis functions, 67–70 hitchhiker’s guide, VIII holography, 547–572 identification, 28, 547–572 ill–conditioned matrix, 91, 96, 235, 237, 338, 341, 362, 415, 424, 531, 555 ill–conditioning, 51, 96, 240, 322, 414, 422 impedance matrix, 26, 367, 369, 371, 376–379, 381, 382, 384 impedance plane, 459–494 masslike, 464–468, 478–480, 486–489 springlike, 467–471, 488, 489 incidence angle of, 150, 168, 181, 182 close to normal, 153 grazing, 481 oblique angle, 154, 167, 170, 179, 180 perpendicular, 460, 474–476, 488–491 table, 528 incident wave, 1, 2, 16–20, 28, 146, 180, 396, 440, 459, 461 infinite boundary elements, 420 576 Index infinite elements, 21, 23, 38, 145, 151, 155, 160–161, 168, 197–250, 420 Astley–Leis elements, 27, 205, 207, 214–215, 218, 221, 222, 231–234, 236–241, 243, 246, 247, 406 Bettess–Burnett elements, 205, 217–218, 221, 222, 232 conjugated, 27, 205–207, 212, 214–215, 218–224, 227, 228, 232, 406 mapped wave envelope elements, 215–219, 231, 232, 236 unconjugated, 205–206, 212–215, 217–219, 221–223, 228, 232 insertion loss, 395 interface acoustic damping material, 253, 255 inverse acoustics, 28, 548 inverse boundary element method (IBEM), 22, 547–572 inverse Fourier transformation, 162, 163, 224, 225, 234, 357 inverse Laplace transform, 158, 496, 502 inverse problem, 548, 568 irregular frequencies, 21, 23, 241, 311, 411–436, 452–453, 457 iterative solver, 21, 23, 57, 73, 89, 96, 105, 231, 232, 235, 239, 241, 246, 247, 316, 330, 333–366, 423, 424, 519, 520, 531, 537, 539, 541 Jacobi polynomial, 24, 231–250 Krylov subspace methods, 232, 235, 333–344, 361 Arnoldi method, 106, 335–337, 339 BiCG, 337, 339 BiCG–Stab, 235, 341, 343, 523 BiCGStab, 337 BiCGStab(l), 337 BiCGStab2, 337 CG, 336, 337 CGNE, 337 CGNR, 337 CGS, 337, 340, 344 GMRes, 235, 336, 337, 340, 344, 345, 361, 423, 424, 523, 531, 532, 537–541 GPBiCG, 337, 342, 344 Lanczos method, 21, 91–95, 100, 108, 109, 335–337, 339 QMR, 105, 235, 339 TFQMR, 235, 243–247, 337 L–curve criterion, 557 Lagrangian elements, 20, 23, 57, 68, 217, 310–312, 329 Lanczos basis, 91, 93, 100 Lanczos type algorithm, 94, 100, 107 Landweber iteration method, 557 Laplace transform, 158, 476, 497, 499, 500, 504, 507, 508, 514 Legendre function, see Legendre polynomial Legendre polynomial, 24, 68–70, 76, 208, 223, 237, 238, 240, 241, 243–245, 309, 311, 314–316, 319, 323, 326, 329, 330, 347, 423, 524 Lighthill’s acoustic analogy, 21, 115–142 line integral, 213, 214, 460, 465–472, 491 Mach number, 116, 121, 127, 128, 139, 220, 221, 503 matched asymptotic expansion (MAE), 128, 131 mean flow, 121, 221, 389, 520, 533 medium frequency range, see mid–frequency range memory consumption, see memory requirement memory requirement, 22, 27, 57, 58, 74, 76, 80–83, 96, 220, 246, 310, 320, 333, 336–339, 343, 344, 358, 360, 362, 367, 381, 384, 395, 436, 520, 531–541, 568 mid–frequency range, VII, 23–25 mirror source method, 460, 464 modal synthesis, 253, 255, 270–275, 284 model reduction, 21, 27, 520 momentum conservation law, see balance of momentum momentum equation, see balance of momentum moving sound source, 502, 503, 505 multi–domain BEM, 367–386, 420 multifield analysis, 26, 28 multifrequency analysis, 26, 89–114 multilevel fast multipole algorithm, see multilevel fast multipole analysis (MLFMA) Index multilevel fast multipole analysis (MLFMA), 21, 333–366, 519–546 nearfield acoustic holography (NAH), 547–572 Neumann problem, see Neumann boundary conditions Newmark scheme, 125, 226, 234, 246, 280, 284 non–existence difficulty, 412 non–reflecting boundary conditions, see absorbing boundary conditions (ABC) non–uniqueness difficulty, 411, 412, 477 operations, see complexity estimate optimization absorbing function (of PML), 169 sound package, 288 structural–acoustic, 2, 25–27 order of convergence, see convergence rate p–FEM, 57, 58, 66–73 Pad´e approximation, 21, 89–93, 95, 96, 100, 105, 153, 154, 162 Pad´e–via–Lanczos, 89–114 panel clustering, 346 Partition of unity method (PUM), 51, 86, 228 perfectly matched layer (PML), 21, 23, 39, 72, 84, 85, 123, 124, 134, 138, 139, 145, 157–161, 164, 167–196, 198, 231 in Cartesian coordinates, 158, 167–186 in polar coordinates, 169, 186–192 Petrov–Galerkin formulation, 50, 233, 336, 337 phase lag, 47, 48 plane wave solution, 19, 490, 491 pollution effect, 20, 37–56, 58, 198, 309, 321, 323, 330 polynomial approximation, 76, 387 incomplete linear, 264 Lagrange, 58, 62, 65–68, 74, 77, 217, 312 orthogonal, 228 Jacobi, 231–250 Legendre, 68–70, 76, 208, 223 Spline, 58, 65, 66 polynomial chaos approximation, 24, 25 poroelastic material, 28, 168, 497, 498, 512, 513 577 porous media, 28, 61, 275, 498 preconditioner, 235–236, 338–344, 531–532 approximate inverse (AIP), 531, 532 block diagonal, 537 block incomplete LU–factorization, 235, 244 diagonal, 338, 539 incomplete Cholesky factorization (IC), 338 incomplete LU–factorization (ILU), 338, 531, 532, 537, 539 ILU(0), 235, 246, 339 ILU(k), 339 ILUT(τ, p), 339, 342, 344 multigrid methods, 96 sparse approximate inverse (SPAI), 339, 537, 539 SSOR, 96, 105 pseudo inverse, 550, 553 quadrature, 486–487 adaptive multigrid, 460, 486, 487, 491 Gauss–Laguerre, 460, 468, 478–480, 486, 487 Gauss–Legendre, 63, 218, 329, 421 Gauss–Lobatto, 73, 76, 77, 80, 81 Newton–Cotes, 76 radial basis function, 232, 233 radial element order, 197, 220–225, 227, 237, 239, 241, 243–247 radial PML method, see perfectly matched layer in polar coordinates radiation modes, 27 Raviart–Thomas elements, 20, 253, 254, 264, 267, 268, 276, 280 reconstruction inverse holographic, 549 of impedance matrix, 26, 27 of sound field, 549 of source parameters, 549, 559, 565, 568 of velocity field, 553 regular grid method (RGM), 340 regularization, 550, 555–560, 565 resolution, 37–56, 65, 66, 83, 117, 128, 135, 137, 198, 207, 241, 360, 392, 550, 565 Reynolds number, 116, 117, 130 rigid plane, 463, 464, 479, 488, 489, 502 578 Index scattering, 20, 38, 146, 147, 161, 167–169, 176–193, 197–199, 209, 220, 310, 333, 346, 367, 368, 411, 417, 420, 422, 432, 435–439, 453, 457, 459–464, 470, 491, 548, 549, 564 Shannon’s sampling theorem, 310 singular value decomposition (SVD), 550, 552, 556, 557 soft plane, 463, 479, 488 Sommerfeld identity, 467 mirror source method, 464–466 radiation condition, 8, 9, 18, 21, 145–149, 168, 199–201, 210, 232, 233, 237, 238, 246, 411, 439, 459, 520 sound power, 26, 27, 72, 395, 411, 430, 431, 461, 560, 561, 563, 564 source dipole, 21, 116, 121, 477, 534, 551, 552 mirror, 463–465 monopole, 10, 16–19, 21, 121, 470, 473, 477, 488, 491, 532 quadrupole, 21, 116, 127, 128 with complex source points, 469–473, 480, 483 source identification, 548, 550, 559, 568 spectral finite element method (SFEM), 21, 57, 58, 73–84, 387–408 spherical Bessel function, 347, 415 spherical Hankel function, 102, 208, 347 spherical harmonics, 347, 351, 352, 356 statistical energy analysis (SEA), 25, 288, 289, 294–298, 302 storage, see memory requirement superconvergence, 223, 309, 311, 319–322 thin–body BEM, 367–386 Tikhonov regularization, 557 time domain BEM, 21, 495–516 classical approach, 495–497, 505–509 convolution quadrature method (CQM), 495–497, 507–509, 511, 512, 514–515 FEM, 21, 75 ABC, 149, 150, 152 aeroacoustics, 117, 125, 130, 133, 134 DtN ABC, 156 FSI, 253, 255, 279–284 infinite elements, 224–228, 231, 232, 234, 246–247 PML, 158, 170–176, 193 SFEM, 58, 73–75 radiation condition, 147–149 transient, see time domain transmission loss, 379, 389, 395–399 Trefftz method, 52 ultra weak variational formulation (UWVF), 52, 86, 228 uncertainty analysis, 23–25 variational multiscale framework (VMS), 48–50 viscoelastic material, 28, 275, 284, 512 viscous damping, 157 viscous effects, 254 viscous fluid, 495, 497–502, 511, 513 viscous stress tensor, 120 wave compression, 497 creeping, 226 cylindrical, 39, 147 elastic, 152, 153, 160 evanescent, 150, 159, 554 plane, 19, 39–42, 51, 52, 86, 147, 157, 159, 167, 170, 179–181, 185, 200, 220, 228, 347, 378, 395, 490, 491 moderately damped, 290, 298, 304 pressure, 152, 177 radio, 467 seismic, 77 shallow water, 168, 221 shear, 152 spherical, 39, 147, 200, 207, 213, 419, 470, 549 spurious, 116 standing, 25 surface, 221, 467, 469, 472, 473 surface gravity, 204 volume, 469 waveguide boundary spectral finite elements, see spectral finite element method (SFEM) This is the end (JM), 578
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