Technical Evaluation Sound Propagation Modelling for Offshore Wind Farms June 1, 2016 Project: 114-362 Prepared for Ministry of the Environment and Climate Change Prepared by Joseph Doran, B.Eng., E.I.T. Guangsheng (Sam) Du, M.Sc., P.Eng. A. D. Lightstone, Ph.D., P.Eng. VALCOUSTICS CANADA LTD. Technical Evaluation: Sound Propagation Modelling – Offshore Wind Farms File: 114-362 Table of Contents Sound Propagation Modelling for Offshore Wind Farms ............................................................................................1 CHAPTER 1 INTRODUCTION ............................................................................................................................1 1.1 Background .................................................................................................................................................1 1.2 Objectives ...................................................................................................................................................1 1.3 Definitions ...................................................................................................................................................2 CHAPTER 2 SOUND PROPAGATION MODEL IDENTIFICATION ..........................................................................4 2.1 Introduction .................................................................................................................................................4 2.2 ISO 9613-2 .................................................................................................................................................4 2.2.1 Summary.................................................................................................................................................4 2.2.2 Basic Equation ........................................................................................................................................5 2.2.3 Attenuation Due to Geometrical Divergence ..........................................................................................5 2.2.4 Attenuation Due to Atmospheric Absorption ...........................................................................................5 2.2.5 Attenuation Due to Ground Effect ...........................................................................................................6 2.2.6 Barrier Attenuation ..................................................................................................................................6 2.2.7 Meteorological Correction .......................................................................................................................7 2.3 Swedish Model ...........................................................................................................................................7 2.3.1 Summary.................................................................................................................................................7 2.3.2 Basic Equation ........................................................................................................................................7 2.4 Danish Model ..............................................................................................................................................8 2.4.1 Summary.................................................................................................................................................8 2.4.2 Basic Equation ........................................................................................................................................8 2.4.3 Low Frequency Noise .............................................................................................................................8 2.5 CONCAWE Model ......................................................................................................................................9 2.5.1 Summary.................................................................................................................................................9 2.5.2 Basic Equation ........................................................................................................................................9 2.5.3 Geometrical Spreading (Divergence) .....................................................................................................9 2.5.4 Atmospheric Absorption ..........................................................................................................................9 2.5.5 Attenuation Due to Ground Effect ...........................................................................................................9 2.5.6 Attenuation Due to Meteorological Effects .......................................................................................... 10 2.5.7 Barrier Shielding .................................................................................................................................. 10 2.5.8 Source/Receiver Height Correction ..................................................................................................... 10 2.5.9 In-Plant Screening ............................................................................................................................... 10 30 Wertheim Court, Unit 25, Richmond Hill, Ontario L4B 1B9 Tel: 905-764-5223/E-mail: [email protected] VALCOUSTICS CANADA LTD. Technical Evaluation: Sound Propagation Modelling – Offshore Wind Farms File: 114-362 2.6 Nordic Prediction Model (Nord2000) ....................................................................................................... 10 2.6.1 Summary.............................................................................................................................................. 10 2.6.2 Basic Equation ..................................................................................................................................... 11 2.6.3 Air (Atmospheric) Absorption ............................................................................................................... 12 2.6.4 Ground Effect ....................................................................................................................................... 12 2.6.5 Ground Impedance .............................................................................................................................. 12 2.6.6 Screen Effect ....................................................................................................................................... 13 2.6.7 Scattering of Sound into the Shadow Zone of a Screen ..................................................................... 13 2.6.8 Terrain Effect ....................................................................................................................................... 13 2.6.9 Incoherent and Averaging Effect ......................................................................................................... 14 2.6.10 Weather Influence ............................................................................................................................ 14 2.6.11 Reflection from Vertical Obstacles .................................................................................................. 15 2.6.12 Scattering Zones .............................................................................................................................. 15 2.7 Harmonoise P2P Model ........................................................................................................................... 16 2.7.1 Summary.............................................................................................................................................. 16 2.7.2 Basic Equation ..................................................................................................................................... 16 2.7.3 Geometrical Attenuation (Divergence) ................................................................................................ 16 2.7.4 Air (Atmospheric) Absorption ............................................................................................................... 16 2.7.5 Ground Effect and Shielding ................................................................................................................ 16 2.7.6 Atmospheric Refraction ....................................................................................................................... 17 2.7.7 Scattering by Atmospheric Turbulence ................................................................................................ 18 2.8 Partial Differential Equation Based Methods ........................................................................................... 18 2.8.1 Summary.............................................................................................................................................. 18 2.8.2 Crank-Nicholson Parabolic Equation (CNPE) Method ........................................................................ 18 2.8.3 Green’s Function Parabolic Equation (GFPE) Method ........................................................................ 19 2.8.4 Fast Field Program (FFP) .................................................................................................................... 20 CHAPTER 3 INTERNATIONAL OFFSHORE MODEL APPLICATION ............................................................ 21 3.1 Introduction .............................................................................................................................................