Predicting Outdoor Sound

Book Cover......Page 1
Title......Page 4
Copyright......Page 5
Contents......Page 6
Preface......Page 10
Symbols......Page 11
1.2 A brief survey of outdoor sound attenuation mechanisms......Page 15
1.3 Data including combined effects of ground and meteorology......Page 16
1.4 Classification of meteorological conditions for outdoor sound......Page 23
1.5 Typical sound speed profiles......Page 28
1.6 Air absorption......Page 35
2.2 Mathematical formulation for a point source near to the ground......Page 39
2.3 The sound field above a locally reacting ground......Page 48
2.4 The sound field above a layered extended-reaction ground......Page 56
2.5 The propagation of surface waves above a porous ground......Page 64
2.6 Experimental data and numerical predictions......Page 68
2.7 The sound field due to a line source near the ground......Page 74
3.1 Introduction......Page 80
3.2 Models for ground impedance......Page 81
3.3 Effects of surface roughness......Page 98
3.4 Effects of ground elasticity......Page 111
4.1 Impedance measurement methods......Page 124
4.2 Comparisons of impedance data with model predictions......Page 132
4.3 Measured and predicted roughness effects......Page 134
4.4 Measured and predicted effects of ground elasticity......Page 144
4.5 Comparisons between ‘template’ fits and direct impedance fits for......Page 149
4.6 Measured flow resistivities and porosities......Page 156
4.7 Effective flow resistivities and other fitted parameters......Page 157
5.2 The sound field due to a dipole source......Page 162
5.3 The sound field due to an arbitrarily orientated quadrupole......Page 182
5.4 Source directivity and railway noise prediction......Page 187
6.1 Approximations for frequency and range dependency......Page 191
6.2 Approximations and data for A-weighted levels over continuous......Page 194
6.3 Predictions of the variation of A-weighted noise over......Page 199
7.1 Introduction......Page 205
7.2 A monopole source moving at constant speed and height above a......Page 206
7.3 The sound field of a source moving with arbitrary velocity......Page 214
7.4 Comparison with heuristic calculations......Page 220
7.5 Diffraction of sound due to a point source moving at constant......Page 224
7.5.2 Diffracted pressure for a source in uniform motion......Page 225
7.6 Source moving parallel to a ground discontinuity......Page 229
7.7 Source moving along a rigid barrier above the ground......Page 236
8.2 Single discontinuity......Page 243
8.3 Propagation over impedance strips......Page 253
8.4 Effects of refraction above mixed impedance ground......Page 258
8.5 Predicted effects of porous sleepers and slab-track on railway......Page 263
9.2 Analytical solutions for the diffraction of sound by a barrier......Page 272
9.3 Empirical formulations for studying the shielding effect of......Page 288
9.4 The sound attenuation by a thin barrier on an impedance ground......Page 293
9.5 Noise reduction by a finite length barrier......Page 299
9.6 Adverse effect of gaps in barriers......Page 301
9.7 The acoustic performance of an absorptive screen......Page 307
9.8 Other factors in barrier performance......Page 310
9.9 Predicted effects of spectral variations in train noise during......Page 317
10.1 Effects of vegetation and crops on excess attenuation spectra......Page 325
10.2 Propagation through trees and tall vegetation......Page 329
10.3 Meteorological effects on sound transmission through trees......Page 335
10.4 Combined effects of vegetation, barriers and meteorology......Page 337
10.5 Turbulence and its effects......Page 339
11.1 Ray tracing......Page 356
11.2 Linear sound speed gradients and weak refraction......Page 366
11.3 Approximations for A-weighted levels and ground effect......Page 369
11.4 A semi-empirical model for A-weighted sound levels at long......Page 389
12.2 ISO 9613–2......Page 394
12.3 CONCAWE......Page 403
12.4 Calculation of road traffic noise (CRTN)......Page 406
12.5 Calculation of railway noise (CRN)......Page 416
12.7 HARMONOISE......Page 418
12.8 Performance of railway noise prediction schemes in high-rise......Page 420
13.1 Introduction......Page 428
13.2 Improved corrections for the reflection of road traffic noise from......Page 429
13.3 Improved correction for the multiple reflections between parallel......Page 431
13.4 Traffic noise attenuation along a city street......Page 434
13.5 Noise in tunnels......Page 436
13.6 Prediction of the acoustic effect of a single building façade with......Page 440
13.7 Sound propagation between two parallel high-rise building......Page 444
13.8 Modelling of 3-D sound propagation between two high-rise......Page 457
13.9 Sound propagation in city streets......Page 467
Index......Page 480