Massachusetts: Officials Guilty Of Systematic Effort Hiding Wind Turbine Documents

Massachusetts Officials Guilty Of Hiding Wind Turbine Documents

Falmouth Confidential Wind Turbine Reports

Cyclic changes in stall conditions generate low frequency sounds.

Wind Turbine Blade Design Review - ResearchGate

Wind Turbine Blade Design Peter J. Schubel * and Richard J. Crossley Faculty of Engineering, Division of Materials, Mechanics and Structures, University of Nottingham, University Park, Nottingham NG7 2RD, UK *
Table 6 Page 3436

An aerodynamic phenomenon known as stall should be considered carefully in turbine blade design.

Stall typically occurs at large angles of attack depending on the aerofoil design.
The boundary layer separates at the tip rather than further down the aerofoil causing a wake to flow over the upper surface drastically reducing lift and increasing drag forces [6].
This condition is considered dangerous in aviation and is generally avoided. However, for wind turbines, it can be utilised to limit the Energies 2012, 5 3437 maximum power output to prevent generator overload and excessive forces in the blades during extreme wind speeds and could also occur unintentionally during gusts.
It is therefore preferable that the onset of the stall condition is not instantaneous for wind turbine aerofoils as this would create excessive dynamic forces and vibrations [1].
References
1. Hau, E. Wind Turbines, Fundamentals, Technologies, Application, Economics, 2nd ed.; Springer: Berlin, Germany, 2006.
6. Burton, T. Wind Energy Handbook; John Wiley & Sons Ltd.: Chichester, UK, 2011.

Falmouth Officials & MassCEC Always Knew About Two Distinct Types of Wind Turbine Noise

DRAFT DNV Review of the Falmouth,
MA Wind-1 and Wind-2 Mitigation Report

CONFIDENTIAL

Town of Falmouth Board of Selectmen c/o Massachusetts Clean Energy Center
55 Summer Street, 9th Floor Boston,
MA 02110 Attention:
Nils Bolgen
DNV Report No.: DDRP0091 March 15, 2012

5.1 Operation of the V82

All wind turbines use some method to limit power production in high winds. The most advanced wind turbines employ a variable speed rotor and reductions of the blade pitch angle to control power production when the power in the wind is greater than the design rating of the system. Blade pitch angle is angle at which the blade axis is set. It is adjusted by the pitch angle mechanism in the rotor hub. Reducing the blade pitch angle reduces the wind power transferred to the drive train.

The V82 wind turbine design has a fixed rotation speed and relies on pitching the blades to greater pitch angles to control power in high winds. This approach reduces the wind power transferred to the drive train by inducing stall along the blade. Stall results in increased turbulence over the blade surface and poor aerodynamic performance. It is an effective means of reducing the power transferred to the drive train but may induce conditions that generate more noise from the blade. Cyclic stall (cyclic changes in stall conditions) can be induced by the changing aerodynamic conditions that blades encounter as they rotate. It is possible that these cyclic changes in stall conditions might generate low frequency sounds.

5.2 Wind Turbine Noise Sources Noise from wind turbines has two main sources, mechanical and aeroacoustic. Mechanical noises stem from such systems as gearboxes, hydraulic pumps and heat exchangers. Mechanical noises are generally easy to isolate, damp or absorb using conventional noise reduction technologies. As a result they are usually a small contributor to overall noise emissions in utility-scale wind turbines unless there is a maintenance problem that needs to be addressed. Aeroacoustic noises are much more difficult to control and make up the largest proportion of noises from modern utility scale wind turbines.

Aeroacoustic noise is often grouped in to two categories:

 Airfoil self-noise – This is noise generated by the normal flow of air over the blades. There are many sources of airfoil self-noise but the most important are trailing edge noise and blade tip vortex noise.

 Turbulent inflow noise – This is noise generated by interactions between the turbulence in the air and the blades. This can be aggravated by changes in flow conditions as the blades rotate.


http://www.falmouthmass.us/energy/DRAFT%20DDRP0091%20DNV%20Review%20of%20Mitigation%20Options%2020120315.pdf


On page 14 of the Marion ,Mattapoisett and Rochester wind test study- 2005

Noise

Noise considerations generally take two forms, state regulatory compliance and nuisance levels at nearby residences:

A. ”Regulatory compliance”: Massachusetts state regulations do not allow a rise of 10 dB or greater above background levels at a property boundary (Massachusetts Air Pollution Control Regulations, Regulation 310 CMR 7.10). This sound level is very unlikely to be a reached incase at the sites we examined.

B.”Human annoyance”: Aside from Massachusetts regulations, residences must also be taken into consideration. Any eventual turbine would be sited such that it would be inaudible or minimally audible at the nearest residences.

The Massachusetts Clean Energy Center knew about “ human annoyance “ noise in the attempt to install wind turbines in Mattapoisett prior to the installations in Falmouth. Today we know human annoyance is infra-sound or low frequency sound.

Everyone in Falmouth including the Select Board, Energy Committee, Board of Health and Town Meeting Members have to ask : WHY WAS THE WARNING TO TWO DISTINCT TYPES OF SOUND DELETED FROM THE FALMOUTH WIND STUDIES AFTER FAILING IN MATTAPOISETT ?

April 2010 Vestas Noise Warning Letter August 3, 2010

Mr. Gerald Potamis, WasteWater Superintendent ,Town of Falmouth Public Works, 59 Town Hall Square, Falmouth, MA 02540

http://www.windaction.org/posts/41357-vestas-raises-concerns-about-turbine-noise-letter#.VRAH-vnF9-c

TOWN OF FALMOUTH COMMUNITY WIND PROJECT SITE SCREENING REPORT April 19, 2005

The Missing Link

The Town of Falmouth failed to post the April 19,2005
FALMOUTH COMMUNITY WIND PROJECT SITE SCREENING REPORT .
TOWN OF FALMOUTH COMMUNITY WIND PROJECT SITE SCREENING REPORT_MTC_KEMA_April 19, 2005

Section 6.2.2 :“ A Special Use Permit is required for construction and operation of windmills in the Town of Falmouth. “

FALMOUTH COMMUNITY WIND PROJECT SITE SCREENING REPORT
“A Special Use Permit is required for construction and operation of windmills in the Town of Falmouth.”

https://www.dropbox.com/s/4cvi5tu6i7yww7a/2005%20April%20KEMA-MTC%20Falmouth_Site_Screening_Study.pdf?dl=0
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