Predicting Outdoor Sound

Early ObservationsA Brief Survey of Outdoor Sound Attenuation MechanismsData Illustrating Ground EffectPropagation from a Fixed Jet Engine SourcePropagation over Discontinuous GroundData Illustrating the Combined Effects of Ground and MeteorologyMore Fixed Jet Engine DataRoad Traffic Noise Propagation over Flat Terrain under Strong Temperature InversionMeteorological Effects on Railway Noise Propagation over Flat TerrainRoad Traffic Noise Propagation in a ValleyClassification of Meteorological Conditions for Outdoor Sound PredictionTypical Sound Speed ProfilesLinear-Logarithmic Representations of Sound Speed ProfilesAir AbsorptionNoteReferences: The Propagation of Sound near Ground Surfaces in a Homogeneous MediumIntroductionA Point Source Above Smooth Flat Acoustically Soft GroundThe Sound Field Above a Locally Reacting GroundThe Sound Field Above a Layered Extended-Reaction GroundSurface Waves Above Porous GroundExperimental Data and Numerical PredictionsThe Sound Field Due to a Line Source Near the GroundReferences: Predicting Effects of Source CharacteristicsIntroductionSound Fields Due to Dipole Sources Near the GroundThe Horizontal DipoleThe Vertical DipoleAn Arbitrarily Orientated DipoleThe Sound Field due to an Arbitrarily Orientated QuadrupoleRailway Noise Directivity and PredictionSource Characteristics of Road TrafficBasic Formulae and ParametersDirectivity CorrectionsOther Corrections and LimitationsSource Characteristics of Wind TurbinesSound-generation MechanismsTypical Spectra of Large Horizontal Axis Wind TurbinesHorizontal and Vertical DirectivityAmplitude ModulationReferences: Numerical Methods Based on Time-Domain ApproachesIntroductionAn Efficient Complete Finite-Difference Time-Domain Model for Outdoor Sound PropagationSound Propagation EquationsNumerical DiscretizationHomogeneous and Still Propagation MediumInhomogeneous MediaMoving MediumStaggered-in-timeCollocated-in-timePrediction-Step Staggered-In-timeNumerical Accuracy and StabilityModelling Propagation in a Moving Unbounded AtmosphereModelling Finite Impedance Boundary ConditionsImpedance Plane ApproachGround Interaction Modelling by Including a Layer of SoilPoro-Rigid Frame ModelPoro-Elastic Frame ModelsLong-Distance Sound Propagation Prediction Based on FDTDMoving Frame FDTDHybrid Modelling: Combining FDTD with GFPEAdvantages of the GFPE MethodComplex Source Region, Simplified Receiver RegionProcedure for One-way Coupling from FDTD to GFPENumerical ExampleComputational Cost ReductionReferences: Predicting the Acoustical Properties of Ground SurfacesIntroductionPredicting Ground ImpedanceEmpirical and Phenomenological ModelsMicrostructural Models Using Idealized Pore ShapesApproximate Models for High Flow ResistivitiesRelaxation ModelsRelative Influence of Microstructural ParametersPhysical Inadmissibility of Semi-Empirical ModelsPredicting Effects of Surface RoughnessBoss and Stochastic ModelsImpedance Models Including Rough Surface EffectsHard Rough SurfacesRough Finite Impedance SurfacesModified ‘Boss’ and Empirical Models for Regularly Spaced Roughness ElementsMultiple Scattering ModelsA Roughness Spectrum ModelPropagation over Rough SeasEffective Impedance of Rough Sea SurfacesPredicted Propagation of Offshore Piling NoisePredicted Rough Sea Effects on Sonic BoomsPredicting Effects of Ground ElasticityCoupling from Airborne Sound to Structures and Ground VibrationBiot-Stoll TheoryNumerical Calculations of Acoustic–Seismic CouplingFast Field Program for Layered Air-Ground Systems (FFLAGS)Example Predictions of Low-Frequency EffectsReferences: Measurements of the Acoustical Properties of Ground Surfaces and Comparisons with ModelsImpedance Measurement MethodsImpedance TubeImpedance MeterNon-Invasive MeasurementsDirect Measurement of Reflection CoefficientImpedance Deduction from Short-Range MeasurementsModel Parameter Deduction from Short-Range Propagation DataA Template Method for Impedance DeductionEffective Flow Resistivity ClassificationDirect Impedance DeductionComparisons of Impedance Spectra with Model PredictionsFits to Short-Range Propagation Data Using Impedance ModelsShort-Range Grassland Data and FitsFits to Data Obtained over Forest Floors, Gravel and Porous AsphaltRailway BallastMeasured Flow Resistivities and PorositiesComparison of Template and Direct Deduction Methods over GrasslandSpatial and Seasonal Variations in Grassland ImpedancePredicted Effects of Spatial VariationMeasured Effects of Varying Moisture ContentInfluence of Water Content on ‘Fast’ and Shear Wave SpeedsMeasured Spatial and Seasonal VariationsGround Effect Predictions based on Fits to Short-Range Level Difference SpectraOn the Choice of Ground Impedance Models for Outdoor Sound PredictionMeasured and Predicted Surface Roughness EffectsRoughness-Induced Ground EffectExcess Attenuation Spectra for Random and Periodic RoughnessRoughness-Induced Surface WavesOutdoor Measurements of the Influence of Roughness on Ground EffectMeasured and Predicted Effects of Ground ElasticityElasticity Effects on Surface ImpedanceGround Vibrations Due to Airborne ExplosionsNon-Linear Interaction with Porous GroundDeduction of Soil Properties from Measurements of A/S CouplingReferences: Influence of Source Motion on Ground Effect and DiffractionIntroductionA Monopole Source Moving at Constant Speed and Height Above a Ground SurfaceThe Sound Field of a Source Moving with Arbitrary VelocityComparison with Heuristic CalculationsPoint Source Moving at Constant Speed and Height Parallel to a Rigid WedgeKinematicsDiffracted Pressure for a Source in Uniform MotionSource Moving Parallel to a Ground DiscontinuityIntroductionUniform Motion Parallel to a Single DiscontinuitySource Moving at Constant Height Parallel to a Rigid Barrier Above the GroundBarrier over Hard GroundBarrier over Impedance GroundSource Moving over Externally Reacting GroundReferences: Predicting Effects of Mixed Impedance GroundIntroductionSingle Impedance DiscontinuityDe Jong’s Semi-Empirical MethodModified De Jong MethodRasmussen’s MethodMultiple Impedance DiscontinuitiesAn Extended De Jong MethodThe nMID (Multiple Impedance Discontinuities) MethodNyberg’s MethodThe Boundary Element MethodComparisons of Predictions with DataSingle Impedance DiscontinuityImpedance StripsRefraction above Mixed Impedance GroundPredicting Effects of Ground Treatments near Surface TransportRoadsSound Propagation from a Road over Discontinuous ImpedancePredicted Effects of Replacing ‘Hard’ by ‘Soft’ Ground Near a RoadPredicting Effects of Low Parallel Walls and LatticesTramwaysRailwaysPorous Sleepers and Porous Slab TrackPredicting Meteorological Effects on the Insertion Loss of Low Parallel WallsConfiguration and GeometryNumerical MethodsMeteorological EffectsPredicting Effects of Variability in Downward-Refraction and Ground ImpedanceIntroductionMeteorological Data and ProcessingGrassland Impedance DataSound Propagation Modelling and Numerical ParametersDetailed Analysis of a Temporal SequenceStatistical Analysis of Temporal Variation over a Full YearSpectral VariationVariation in A-Weighted Pink NoiseConvergence to Yearly L AeqConclusionsReferences: Predicting the Performance of Outdoor Noise BarriersIntroductionAnalytical Solutions for the Diffraction of Sound by a BarrierFormulation of the ProblemThe MacDonald SolutionThe Hadden and Pierce Solution for a WedgeApproximate Analytical FormulationEmpirical Formulations for Studying the Shielding Effect of BarriersThe Sound Attenuation by a Thin Plane on the GroundNoise Reduction by a Finite-Length BarrierAdverse Effect of Gaps in BarriersThe Acoustic Performance of an Absorptive ScreenGabion BarriersNumerical Predictions of Comparative Acoustical PerformanceLaboratory Measurements on Porous-Stone GabionsOutdoor Measurements on a Gabion BarrierOptimizing Gabion Barriers for Noise ReductionOther Factors in Barrier PerformanceBarrier ShapeMeteorological Effects on Barrier PerformanceRough and Soft BermsBerms vs Barriers in WindSonic Crystal Noise BarriersPredicted Effects of Spectral Variations in Train Noise During Pass-byReferences: Predicting Effects of Vegetation, Trees and TurbulenceMeasured Effects of VegetationInfluence of Vegetation on Soil PropertiesMeasurements of Sound Transmission through VegetationMeasured Attenuation due to Trees, Shrubs and HedgesPredicting Sound Transmission through VegetationGround Effect with Plants and VegetationModels for Foliage EffectsEmpirical ModelsScattering ModelsReduction of Coherence by ScatteringPredictions of Ground Effect, Scattering and Foliage AttenuationSound Propagation in CropsSound Propagation in ForestsInfluence of Ground on Propagation Through Arrays of Vertical CylindersLaboratory Data Combining ‘Sonic Crystal’ and Ground EffectsNumerical Design of Tree Belts for Traffic Noise ReductionMeasured and Predicted Effects of Irregular Spacing in the LaboratoryReflection from Forest EdgesMeteorological Effects on Sound Transmission Through TreesCombined Effects OF Trees, Barriers and MeteorologyTurbulence and its EffectsTurbulence MechanismsModels for Turbulence SpectraClifford and Lataitis Prediction of Ground Effect in Turbulent ConditionsOstashev et al. Improvements on the Clifford and Lataitis ApproachHeight Dependence of TurbulenceTurbulence-Induced Phase and Log-Amplitude FluctuationsScattering by TurbulenceDecrease in Sound Levels due to TurbulenceMeasurement of TurbulenceInclusion of Atmospheric Turbulence in the Fast Field ProgramComparisons with Experimental DataIncluding Turbulence in FDTD CalculationsEquivalence of Turbulence and Scattering Influences on CoherenceReferences: Ray Tracing, Analytical and Semi-empirical Approximations for A-Weighted LevelsRay TracingLinear Sound Speed Gradients and Weak RefractionApproximations for A-Weighted Levels and Ground Effect Optimization in the Presence of Weak Refraction and TurbulenceGround Effect OptimizationIntegral Expressions for A-Weighted Mean Square Sound PressureApproximate Models for Ground ImpedanceEffects of Weak RefractionApproximations for Excess AttenuationVariable Porosity or Thin Layer GroundRough GroundSmooth High Flow Resistivity GroundNumerical Examples and DiscussionComparison with Data: Avon Jet Engine SourceSensitivity to Spectrum, Source Height and DistanceVariation with DistanceEffects of RefractionConcluding RemarksA Semi-Empirical Model for A-Weighted Sound Levels at Long RangeReferences: Engineering ModelsIntroductionISO 9613–2DescriptionBasic EquationsGeometrical DivergenceAtmospheric AbsorptionGround EffectScreeningMeteorological CorrectionGeneral CritiqueCONCAWEIntroductionBasis and Provisions of SchemeCriticisms of CONCAWECalculation of Road Traffic Noise (CRTN)IntroductionBasic EquationsL 10 LevelsCorrections for Mean Traffic Speed, Percentage of Heavy Vehicles and GradientCorrection for Type of Road SurfaceDistance CorrectionGround Cover CorrectionScreening CorrectionSite LayoutSegments and Road JunctionsCalculation of Railway Noise (CRN)NORD2000HARMONOISEIntroduction and BackgroundGeneral MethodologyBasic EquationsIdentification of Propagation PlanesRecommended Numerical TechniquesMeteorological ConditionsFrequency ResolutionLong-term Integrated LevelsValidationAnalytical Point-to-point ModelIntroductionMethodology for Combining Ground and Barrier EffectGround Reflection ModelSound Diffraction ModelSingle DiffractionMultiple DiffractionsTransition ModelRefractionCoherence LossesScattering by TurbulenceThe Environmental Noise Directive (END) Scheme (CNOSSOS-EU)Ground EffectCriticismsPerformance of Railway Noise Prediction Schemes in High-Rise CitiesPerformance of Engineering Models in a Complex Road Traffic Noise ExampleSite and ModelsApproximating the Berm SlopeRoad Traffic Source Power ModellingDaytime vs Nighttime Measurements and PredictionsModel PerformancePredicting Wind Turbine NoiseAn Untypical Industrial SourceComplex Meteorologically Induced Propagation EffectsGround Effect for Wind Turbine Sound PropagationPropagation over Non-Flat TerrainPrediction Requirements for Outdoor Sound AuralizationIntroductionSimulating Outdoor Attenuation by FiltersAuralization of a Noise Abatement Based on a Priori RecordingsReferences