Acoustics and Particle Velocity Monitoring : Block Island Wind Farm

Transcription

1 Acoustics and Particle Velocity Monitoring : Block Island Wind Farm Workshop: Atlantic Offshore Renewable Energy Development and Fisheries The National Academies of Sciences, Engineering and Medicine November 8 and 9, 2017

2 Outline Introduction: Acoustic pressure and particle velocity Modeling acoustic propagation Fish hearing and effect of noise and particle motion BIWF Field measurements details Pressure and Particle motion measurements During construction During operation Future work

3 Acoustic Waves

4

5 Acoustic Particle Velocity The acoustic particle motion is related to the acoustic scalar field (i.e., pressure) by the momentum equation for acoustic processes Geophone: direct measurement of the acoustic particle velocity Crocker and Fratantonio, Characteristics of Sounds Emitted During High-Resolution Marine Geophysical Surveys, NUWC-NPT Technical Report 12, March 2016 MacGillivray and Racca, Sound pressure and particle velocity measurements from marine pile driving with bubble curtain mitigation, Canadian Acoustics, Vol. 34 No. 3 (2006)

6 Acoustic propagation modeling

7 Pile Driving: Mach Wave

8 Vertical Pile: FEM Analysis Time domain analysis Abaqus FEM code Cylindrical pile Air Axisymmetric model Water Bottom FE result of construction noise model for a single impact (Reproduction of Reinhall & Dahl s work) Kim, PhD Dissertation, URI, 2004 Reinhall, P.G. and P.H. Dahl, Acoustic radiation during marine pile driving. The Journal of the Acoustical Society of America, (4): p. 2460

9 Scholte Waves (Ground Roll) Decay exponentially in amplitude away from the boundary in either medium( i.e., the wave is evanescent in both media). Propagate along the interface u w From Osler and Chapman, Canadian Acoustics, 24(3), 1996 Dosso and Brooke, J. Acoustic. Soc. A., 98(3), 1995 Rauch, Seismic interface waves in coastal waters: A review, SACLANT Report, 1980

10 Scholte Wave (Ground Roll) Wave propagation direction water sediment

11 Finite Element Monitoring BIWF 3-D Modeling ongoing with collaboration from Sandia National Labs

12 Fish hearing and effect of noise and particle motion

13 Fish Hearing Auditory portions of the fish ears are the otolithic organs Each otolithic organ consists of a dense calcareous mass contacting a sensory epithelium. Otolithic organs of all fishes respond to particle motion of the surrounding fluid. Many fishes are also able to detect sound pressure via the gas bladder or other gas-filled structures that re-radiate energy, in the form of particle motion, to the otolithic organs

14 Anthropogenic Noise Sources and hearing ranges of fishes and marine mammals

15 Fish hearing sensitivity Fish with gas-filled structures near the ear and/or extensions of the swim bladder respond to fluctuating sound pressure, generating particle motion. They have lower sound pressure thresholds and wider frequency ranges of hearing than do the purely particle motionsensitive species

16 Particle motion sensitivity Hearing range and sensitivity varies considerably among species Behavioral audiograms have been published for only a few species of fish and there are concerns about the usefulness of many of these Poorly monitored acoustic conditions and it is difficult to determine whether the fish were responding to sound pressure or particle motion Noise can result in the audiograms being masked so that the full hearing sensitivity of the animal cannot be determined. Auditory evoked potentials may not fully reflect the hearing capabilities of animals - do not include signal processing by the brain

17 Sound Exposure Effects Mortality and mortal injury immediate or delayed death. Recoverable injury injuries, including hair cell damage, minor internal or external hematoma, etc. None of these injuries are likely to result in mortality. TTS short or long term changes in hearing sensitivity that may or may not reduce fitness. TTS, for these Guidelines, is defined as any change in hearing of 6 db or greater that persists. This level is selected since levels less than 6 db are generally difficult to differentiate. Masking impairment of hearing sensitivity by greater than 6 db, including all components of the auditory scene, in the presence of noise. Behavioral effects substantial change in behavior for the animals exposed to a sound. This may include long-term changes in behavior and distribution, such as moving from preferred sites for feeding and reproduction, or alteration of migration patterns.

18 Sound Exposure Guidelines 1. There are more than 32,000 species of fish; 2. Fishes are much more diverse anatomically, physiologically, ecologically, and behaviorally; 3. Most fishes respond to the particle motion component of sound waves; 4. Relatively few papers link exposure to effects in fishes; 5. Very little is known about their hearing and the role of sound in their lives sea turtles; it is very difficult to establish guidelines

19 Guidelines: Pile Driving

20 New ISO Standard Working group (ISO TC43 SC3 WG3) did not consider particle velocity The working group meeting at WHOI last month decided to wait until more data is collected before working on particle velocity.

21 Block Island Wind Farm Monitoring

22 Block Island Wind Farm

23 Block Island Wind Farm

24 Real Time Opportunity for Development Environmental Observations (RODEO) The RODEO Team BOEM Program Manager: Mary Boatman HDR PIs: Anwar Khan and Randy Gallien Gopu R. Potty and James H. Miller University of Rhode Island Kathy Vigness Raposa and Jennifer Amaral Marine Acoustics Inc. Y.-T. Lin and Arthur Newhall Woods Hole Oceanographic Institution Tim Mason Subacoustech Environmental Ltd., UK Study concept, oversight, and funding were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program, Washington, DC under Contract Number M16PD00025.

25 Particle motion measurements: 3-axis geophone and 4 hydrophones on a tetrahedral array (0.5 m spacing)

26 Block Island Wind Farm Monitoring The diameter of each pile between 42 inches (in) and 54 in (107 centimeters [cm] and 137 cm), with a maximum wall thickness of 1.5 in (3.8 cm). Design penetration up to 250 ft into the bottom, Three field data collection efforts Construction (during pile driving) (October November, 2015 Operation ( Decemeber, January, 2017 And October-November, 2017)

27 Geophysical sled A geophysical sled with a 4 hydrophone tetrahedral array (for measurement of acoustic particle velocity) and a 3-D geophone with low sensitivity hydrophone (for the measurement of sediment motion) was deployed about 500 meters from WTG #3 and #4 in about 26 meters of water. VLA s were at 7.5 km and 15 km range. On the right is a photo of the surface floats for the sled with WTG#4 in the background.

28 Data collected during construction and Operation of the turbine

29 Summary of measurements during construction

30 Tetrahedral Array Acoustic pressure for one hammer strike measured at 500 m from the turbine by the four hydrophones on the tetrahedral array October 25, 2015; UTC Acoustic pressure on the seabed SPL=186 db re 1μPa

31 Particle Velocity (Construction): Geophone vs Tetrahedral Array Geophone Tetrahedral Array

32 Effect of Scholte waves (ground roll) Low frequencies (possibly corresponding to Scholte waves or ground roll) dominates the geophone signal. Scholte waves propagate along the interface and decay exponentially away from the interface into the sediment and water column.

33 Particle Accelerationon the seabed Frequency distribution of acceleration for one hammer strike calculated from geophone data at 500 m from the turbine October 25, 2015; UTC Tetrahedral Array data Geophone data

34 Particle Velocity Tetrahedral Array: Operational

35 Particle Velocity: Operational Acoustic Pressure (tetrahedral array) Acoustic Pressure (seabed)

36 Particle Velocity (Operational): Geophone Vs Tetrahedral Array 40 db re 1 nm/sec

37 Fish hearing sensitivity Particle velocity levels well below hearing sensitivity during operation

38 Future Work Measurements: Measurements this summer/ Fall to investigate seasonal variability (just finished) Modeling: Finite Element Modeling of raked pile-fluid sediment-air interaction problem (Graduate student Ragusa in collaboration with Sandia National Laboratories)

39 RODEO Program Study concept, oversight, and funding were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program, Washington, DC under Contract Number M16PD Recreational fishing boat near Turbine #5

40 Questions